Electrostatic chuck device and temperature control method

Abstract

The present application discloses an electrostatic chuck device and a temperature control method. The electrostatic chuck device includes a device base, a heating layer, and an insulating adsorption layer arranged in sequence from bottom to top. The heating layer is provided with at least two main heaters, and the main heaters are used to heat the wafer carried by the electrostatic chuck device. The insulating adsorption layer is provided with an adsorption electrode, and the adsorption electrode is used to adsorb the wafer. The electrostatic chuck device also includes a controller. The insulating adsorption layer is also provided with a plurality of compensation heaters, and the plurality of compensation heaters are insulated from the adsorption electrodes and electrically connected to the controller. The controller is used to control the opening or closing of each compensation heater and the power of each compensation heater. The above technical solution can solve the problem of poor process uniformity of the workpiece due to the possible deviation of temperature at different positions on the workpiece.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor processing technology, and specifically relates to an electrostatic chuck device and a temperature control method. Background Art

[0002] During the processing of semiconductor workpieces such as wafers, heaters, such as electrostatic chucks, are often used to heat the wafers and other workpieces to improve process efficiency and / or process performance, thereby increasing the overall temperature of the workpiece. However, in actual processing, due to various reasons, the temperature at different locations on the workpiece supported by the same heater may vary, resulting in poor process uniformity. Summary of the Invention

[0003] The present application discloses an electrostatic chuck device and a temperature control method, which can solve the problem of poor process uniformity of a workpiece due to possible temperature deviations at different positions on the workpiece.

[0004] In order to solve the above problems, the embodiment of the present application is implemented as follows:

[0005] In the first aspect, an embodiment of the present application provides an electrostatic chuck device for semiconductor equipment, wherein the electrostatic chuck device includes a device base, a heating layer, and an insulating adsorption layer arranged in sequence from bottom to top, wherein at least two main heaters are provided in the heating layer, and the main heaters are used to heat the wafer carried by the electrostatic chuck device, and the insulating adsorption layer is provided with an adsorption electrode, and the adsorption electrode is used to adsorb the wafer; the electrostatic chuck device also includes a controller, and a plurality of compensation heaters are also provided in the insulating adsorption layer, and the plurality of compensation heaters are all insulated from the adsorption electrode, and the plurality of compensation heaters are all electrically connected to the controller, and the controller is used to control the opening or closing of each of the compensation heaters, and to control the power of each of the compensation heaters.

[0006] In a second aspect, an embodiment of the present application discloses a temperature control method, which is applied to the above-mentioned electrostatic chuck device, wherein the electrostatic chuck device is used to carry and heat a wafer, and the temperature control method includes:

[0007] S1. Establishing a correspondence between process steps and target compensation heaters, wherein the target compensation heaters are the remaining compensation heaters among the multiple compensation heaters except the compensation heaters corresponding to the positions where the extreme values ​​of the multiple original process results are located when performing each process step; the original process results are process results at positions corresponding to the multiple compensation heaters on the wafer when performing each process step while keeping the at least two main heaters in the heating layer turned on and keeping all the compensation heaters turned off; when the process result is positively correlated with the temperature at the corresponding position on the wafer, the extreme value is the maximum value; when the process result is negatively correlated with the temperature at the corresponding position on the wafer, the extreme value is the minimum value;

[0008] S2. Acquire the process step to be performed, control each of the main heaters in the heating layer to be turned on, and control each of the target compensation heaters corresponding to the process step to be performed to be turned on according to the corresponding relationship.

[0009] The present application discloses an electrostatic chuck device that can be used in semiconductor equipment. In the electrostatic chuck device, an insulating adsorption layer is stacked on a heating layer, which is stacked on a device base. At least two main heaters in the heating layer can heat a wafer carried on the electrostatic chuck device, and adsorption electrodes in the insulating adsorption layer can adsorb electrodes, thereby ensuring that the wafer can be stably supported on the electrostatic chuck device. At the same time, the electrostatic chuck is provided with a controller, and multiple compensation heaters are also provided in the insulating adsorption layer. The multiple compensation heaters are all electrically connected to the controller, and the controller can control the turning on or off of each compensation heater and the power of each compensation heater. Subsequently, by detecting process results such as the etching rate at different locations on the wafer, the temperature conditions at corresponding locations on the wafer can be indirectly obtained through multiple process results. Therefore, if the temperature at different locations on the wafer is inconsistent when the wafer is heated only by the main heater in the heating layer during certain processes, the controller can be used to control the activation of at least one corresponding compensation heater in the electrostatic chuck device and control the operating power of the activated compensation heater so that the activated compensation heater can heat the corresponding location on the wafer, raising the temperature at the location to the same as the highest temperature value on the wafer (i.e., the maximum or minimum value of the process result on the wafer), thereby ensuring relatively high process uniformity of the wafer. In addition, since the power of the compensation heater is relatively small compared to the power of the main heater, by locating the compensation heater in the insulating adsorption layer at a short distance from the electrostatic chuck device, the heat of the compensation heater can be transferred to the area corresponding to the compensation heater more quickly and accurately, thereby providing thermal compensation for the corresponding location on the wafer and achieving a faster response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0011] Figure 1 Schematic diagram of the structure of the electrostatic chuck device disclosed in the embodiment of the present application;

[0012] Figure 2 Schematic diagram of the structure of the insulating adsorption portion of the electrostatic chuck device disclosed in the embodiment of the present application;

[0013] Figure 3 Schematic diagram of the distribution of multiple compensation heating parts in the electrostatic chuck device disclosed in the embodiment of the present application;

[0014] Figure 4 Schematic diagram of the structure of the adsorption electrode in the electrostatic chuck device disclosed in the embodiment of the present application;

[0015] Figure 5 Schematic diagram of the electrical principle of the electrostatic chuck device disclosed in the embodiment of the present application;

[0016] Figure 6 This is a schematic diagram of the electrical principle of part of the structure of the electrostatic chuck device disclosed in the embodiment of the present application;

[0017] Figure 7 is a flow chart of the temperature control method disclosed in an embodiment of the present application;

[0018] Figure 8 Schematic diagram of the position distribution of multiple temperature-measured points on a wafer in the temperature control method disclosed in an embodiment of the present application;

[0019] Figure 9 It is a schematic diagram of the relative positions between multiple temperature-measured points on a wafer and a compensation heater in the temperature control method disclosed in an embodiment of the present application;

[0020] Figure 10 This is a schematic diagram of temperature comparison of multiple measured points on a wafer when the compensation heater is in the on and off states in the temperature control method disclosed in an embodiment of the present application.

[0021] Description of reference numerals:

[0022] 100-compensation heater,

[0023] 210-control unit, 220-execution unit,

[0024] 300-heating layer,

[0025] 400-device base,

[0026] 500-insulating adsorption layer, 510-third insulating sublayer, 520-second insulating sublayer, 530-first insulating sublayer, 540-adsorption sublayer, 550-compensating heating layer,

[0027] 610-Filter, 620-Power filter box. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The technical solutions disclosed in various embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0030] like Figure 1-Figure 5 As shown, an embodiment of the present application discloses an electrostatic chuck device, which can be used in semiconductor equipment to use the electrostatic chuck device to carry wafers and other workpieces, and change the temperature of wafers and other workpieces to improve process efficiency and the excellence of process results. The electrostatic chuck device includes a device base 400, a heating layer 300 and an insulating adsorption layer 500, and the device base 400, the heating layer 300 and the insulating adsorption layer 500 are arranged from bottom to top. It should be noted that the aforementioned up and down directions are the directions of the vertical direction during the normal working process of the electrostatic chuck, which can be more intuitively Figure 1 Direction A in.

[0031] The heating layer 300 is provided with at least two main heaters, which are capable of heating the wafers carried by the electrostatic chuck device, raising the temperature of the wafers and improving the process efficiency and effect of the wafers. The main heaters can specifically include heating devices such as resistance wires to ensure that the main heaters have heating capacity. The number of main heaters can be two, three, or more, and the number of main heaters can be determined based on parameters such as the size and shape of each main heater, which is not limited here. The multiple main heaters can be fan-shaped and together form the complete heating area of ​​the heating layer 300. In another embodiment of the present application, one of the main heaters is a circular structure, and the remaining ones are annular structures. The multiple main heaters are assembled in a nested manner to form the heating area of ​​the heating layer 300. This distribution of the main heaters can control the size of the heating area based on the diameter and other dimensions of the workpiece, such as the wafer, and has relatively high control accuracy. Of course, in addition to the main heaters, the heating layer 300 can also include a structure to fix the main heaters, specifically a molding material such as quartz or ceramic. The multiple main heaters can be embedded in the molding material such as quartz or ceramic to form a structurally stable heating layer 300.

[0032] The insulating adsorption layer 500 is provided with an adsorption electrode, which can adsorb the wafer so that the wafer can be stably supported and fixed on the electrostatic chuck device. The adsorption electrode can be formed by printing, and its specific shape and structure can be determined according to actual conditions, such as Figure 4 As shown, the adsorption electrode is divided into two regions, DC+ and DC-. The adsorption electrode can be an annular structure, formed by winding a metal wire in multiple turns. Furthermore, the adsorption electrode can be formed within a molding material such as quartz or ceramic to form an insulating layer. This not only secures the adsorption electrode, but also provides insulation to the insulating adsorption layer 500, thereby preventing adverse effects on the normal operation of the compensation heater 100 disposed within the adsorption insulating layer, as described below.

[0033] In addition, the electrostatic chuck device disclosed in the embodiment of the present application also includes a controller, and a plurality of compensation heaters 100 are provided in the insulating adsorption layer 500. Each compensation heater 100 can also heat the insulating adsorption layer 500 when in operation, so that the temperature of the area where each compensation heater 100 is located is compensated, thereby increasing the temperature of the area where each compensation heater 100 is located. At the same time, the plurality of compensation heaters 100 are insulated from the adsorption electrode.

[0034] Specifically, each compensating heater 100 may include a heating device such as a resistance wire. Of course, its specific shape, size and other parameters can be determined according to actual needs and are not limited here. The number of compensating heaters 100 can be determined according to actual parameters such as the size and shape of the compensating heater 100 and the size and shape of the insulating adsorption layer 500, and is not limited here. More specifically, the heating power of each compensating heater 100 can be made substantially the same to reduce the difficulty of controlling multiple compensating heaters 100 and improve the temperature control accuracy of the electrostatic chuck device. In addition, the compensating heater 100 can also be formed in a molding material such as quartz or ceramic in the insulating adsorption layer 500, and by spacing the compensating heater 100 and the adsorption electrode from each other in the thickness direction of the insulating adsorption layer 500, it is ensured that each compensating heater 100 can be insulated from the adsorption electrode.

[0035] In a specific embodiment, multiple compensation heaters 100 can be positioned at the same position in the insulation adsorption layer 500 along the thickness direction of the insulation adsorption layer 500, and the multiple compensation heaters 100 can be evenly distributed, so that each compensation heater 100 can correspond to a different area in the insulation adsorption layer 500, and the areas corresponding to the multiple compensation heaters 100 together constitute the entire surface of the insulation adsorption layer 500. Figure 3 As shown, the compensation heater 100 can be distributed in a ring structure as a whole, and the compensation heaters 100 in any ring structure are distributed circumferentially. The structure and size of the compensation heaters 100 included in each ring structure can be determined according to actual conditions and are not limited here.

[0036] It should be noted that the size of each compensation heater 100 can be made relatively small, and in the process of arranging the compensation heater 100, the distribution of the compensation heater 100 can be made as uniform as possible, which can enhance the ability of the compensation heater 100 to perform temperature compensation on the electrostatic chuck device relatively strongly and more comprehensively.

[0037] As described above, the electrostatic chuck device disclosed in the embodiments of the present application includes a controller. Based on this, multiple compensating heaters 100 can be electrically connected to the controller, so that the controller can control the on / off state of each compensating heater 100 and the power of each compensating heater 100. During the operation of the electrostatic chuck device, corresponding control rules can be pre-set for the controller, allowing the controller to control the compensating heater 100 corresponding to the process step to be performed based on the pre-set control rules according to the specific circumstances of the process step to be performed.

[0038] More specifically, before the electrostatic chuck device is implemented in mass production, its heating characteristics can be pre-tested. During this test, only the main heaters in the heating layer 300 are turned on, while the multiple compensation heaters 100 are kept off. The temperatures at multiple locations on the electrostatic chuck are then measured. These locations correspond one-to-one with the locations of the compensation heaters 100, thereby generating a large amount of basic data.

[0039] Of course, during the measurement process, since the measurement difficulty of temperature data is relatively large, it is possible to measure parameters such as the etching rate at different positions on a workpiece such as a wafer, and thus use parameters such as the etching rate that are directly related to the temperature to characterize the specific situation of the temperature at that position on the wafer, that is, the above-mentioned basic data can specifically be the etching rate. In addition, parameters such as the etching rate may be directly proportional to the temperature, or may be inversely proportional. For the convenience of the following description, the following takes the example of the etching rate of the wafer being proportional to the temperature. It should be noted that the multiple measured positions can specifically be the structural center of each compensation heater 100. Of course, the measured positions can also be the edge of each compensation heater 100. It is only necessary to ensure that the measured positions on the multiple compensation heaters 100 correspond to each other.

[0040] Moreover, due to various factors such as different heat conduction conditions at different positions on the electrostatic chuck device, the sizes of the above-mentioned multiple basic data may be different. Based on this, the compensation heater 100 corresponding to the basic data can be turned on and the position where the compensation heater 100 is located can be heated to increase the temperature of the area where the compensation heater 100 is located, thereby achieving the purpose of reducing or even eliminating the difference between the one with the largest value among the multiple basic data and the basic data, so that the differences between the multiple basic data are relatively small, or even the differences between the multiple basic data are all zero.

[0041] During the above-mentioned test process, the controller can be used to control the on or off of each compensation heater 100, that is, the compensation heater 100 corresponding to the highest etching rate on the wafer is in the off state, and the compensation heaters 100 corresponding to other positions on the wafer with an etching rate lower than the aforementioned highest one are in the on state. These on-state compensation heaters 100 are used to perform temperature compensation on their respective positions, so that the temperature of the area on the wafer corresponding to multiple on-state compensation heaters 100 is increased, thereby increasing its etching rate.

[0042] Although the compensation heater 100 corresponding to the position with a relatively low etching rate on the wafer can increase the etching rate at the aforementioned position when it is turned on, the compensation heater 100 in the turned-on state may increase the temperature at its location to a temperature exceeding the temperature at the position with the highest temperature on the wafer, thereby causing the etching rate at this position to become the new position with the highest etching rate, which may cause the etching rate at different positions on the wafer to still have an increasing difference. Based on this, the controller can also control multiple compensation heaters 100 to operate at different powers, so that the compensation heaters 100 in the turned-on state can compensate the temperature of the corresponding area to a state close to or even the same as the highest temperature on the wafer, ensuring that the etching rate at different positions on the wafer is relatively consistent.

[0043] The activation powers of the multiple compensation heaters 100 can also be obtained through pre-testing. Specifically, based on the specific process to be performed, the compensation heaters 100 corresponding to the areas on the wafer where the etch rate is less than the maximum value can be activated at different powers, and the power value closest to the maximum etch rate can be recorded. During mass production, as long as the aforementioned process is performed, the controller can be used to control the compensation heaters 100 to activate at the power value obtained in the aforementioned test, so that the temperature and etch rate of the areas on the wafer corresponding to the compensation heaters 100 can both correspond to the maximum temperature and etch rate on the wafer, ensuring high process uniformity across the wafer.

[0044] The present application discloses an electrostatic chuck device that can be used in semiconductor equipment. In the electrostatic chuck device, an insulating adsorption layer 500 is stacked on a heating layer 300, which is stacked on a device base 400. At least two main heaters in the heating layer 300 can heat a wafer carried on the electrostatic chuck device. The adsorption electrodes in the insulating adsorption layer 500 can adsorb electrodes, thereby ensuring that the wafer can be stably supported on the electrostatic chuck device. At the same time, the electrostatic chuck is provided with a controller, and a plurality of compensation heaters 100 are also provided in the insulating adsorption layer 500. The plurality of compensation heaters 100 are all electrically connected to the controller, and the controller can control the turning on or off of each compensation heater 100, as well as the power of each compensation heater 100. Then, by detecting process results such as the etching rate at different positions on the wafer, the temperature conditions at corresponding positions on the wafer can be indirectly obtained through multiple process results. Therefore, if the wafer is heated only by the main heater in the heating layer 300 during certain processes, and there is a temperature inconsistency at different positions on the wafer, when performing the aforementioned process, the controller can be used to control at least one corresponding compensation heater 100 in the electrostatic chuck device to turn on, and the working power of the compensation heater 100 in the turned-on state can be controlled, so that the turned-on compensation heater 100 can heat the corresponding position on the wafer, so that the temperature at the position rises to the same as the highest temperature value on the wafer (that is, the maximum or minimum value of the process results on the wafer), thereby ensuring that the process uniformity of the wafer is relatively high. Moreover, since the power of the compensation heater 100 is relatively small compared to the power of the main heater, by locating the compensation heater 100 in the insulating adsorption layer 500 which is closer to the electrostatic chuck device, the heat of the compensation heater 100 can be transferred to the area corresponding to the compensation heater 100 faster and more accurately, thereby providing heat compensation for the corresponding position of the wafer, and the response speed is faster.

[0045] As described above, the insulating adsorption layer 500 including the compensation heater 100 and the adsorption electrode can be formed by integral molding or the like. Specifically, ceramic material can be arranged between the compensation heater 100 and the adsorption electrode, as well as outside the compensation heater 100 and the adsorption electrode, by integral sintering. The compensation heater 100 and the adsorption electrode can be fixed in the ceramic material by sintering to form the insulating adsorption layer 500.

[0046] In another embodiment of the present application, optionally, as Figure 2As shown, the insulating adsorption layer 500 includes a first insulating sublayer 530, a second insulating sublayer 520, and a third insulating sublayer 510, arranged in order from bottom to top. The first insulating sublayer 530, the second insulating sublayer 520, and the third insulating sublayer 510 are all insulating structural members. That is, all three are formed of insulating materials such as ceramics and can be plate-shaped or layered structures to ensure mutual insulation between devices located on opposite sides of any of the three members.

[0047] Furthermore, the adsorption electrode is disposed between the third insulating sublayer 510 and the second insulating sublayer 520 to form an adsorption sublayer 540, and the multiple compensation heaters 100 are disposed between the second insulating sublayer 520 and the first insulating sublayer 530 to form a compensation heating layer 550. That is, in this embodiment, the adsorption electrode and the compensation heater 100 are insulated from each other by the molded structural member, the second insulating sublayer 520, thereby ensuring relatively reliable insulation between the adsorption electrode and the compensation heater 100 in the formed insulating adsorption layer 500. Furthermore, the prefabrication of the first insulating sublayer 530, the second insulating sublayer 520, and the third insulating sublayer 510 provides a fixed foundation for the adsorption electrode and the compensation heater 100, further enhancing the relative positional stability between the adsorption electrode and the compensation heater 100. This prevents the adsorption electrode and / or the compensation heater 100 from shifting relative to their original positions during the integral molding process of the adsorption electrode, the compensation heater 100, and the insulating material, thereby ensuring that the adsorption electrode, and particularly the multiple compensation heaters 100, remain at their preset positions, thereby improving the heating uniformity of the entire electrostatic chuck.

[0048] Specifically, the first insulating sublayer 530, the second insulating sublayer 520, and the third insulating sublayer 510 are all thin sheet-like structures formed by mixing ceramic particles with an adhesive. Subsequently, multiple compensating heaters 100 can be placed on the first insulating sublayer 530. Each compensating heater 100 can be an independent electric heating device. The specific positions of the multiple compensating heaters 100 can be determined based on pre-tested heating of the heating layer 300, so that the multiple compensating heaters 100 are as close as possible to locations on the heating layer 300 where the heating temperature on the wafer is relatively low. Of course, the multiple compensating heaters 100 can also be evenly distributed on the first insulating sublayer 530, and the compensating heaters 100 that need to be activated during the process are determined based on the specific process type. Next, the second insulating sublayer 520 is pressed and covered on the side of the compensating heating layer 550 facing away from the first insulating sublayer 530. An adsorption electrode is then formed on the second insulating sublayer 520 by printing or other methods. Finally, the third insulating sublayer 510 is pressed and applied over the adsorption layer to form the overall structure of the insulating adsorption layer 500. Finally, by integral sintering, the adsorption electrode and the compensation heater 100 can be reliably fixed in the first insulating sub-layer 530 , the second insulating sub-layer 520 and the third insulating sub-layer 510 , forming an insulating adsorption layer 500 with a stable structure.

[0049] Optionally, the compensating heater 100 includes a metal resistance heater formed by screen printing, which can reduce the difficulty of processing multiple compensating heaters. In addition, the cables of the compensating heater 100 pass through the device base 400 and the heating layer 300 and are led out of the device base 400, so that the device base 400 and the heating layer 300 can provide protection for the cables of the compensating heater 100, and the cables of the multiple compensating heaters 100 can be bundled, reducing the difficulty of organizing the cables of each compensating heater 100. In addition, the number of compensating heaters 100 can be greater than or equal to 10 and less than or equal to 100, thereby ensuring that the heating layer 300 is provided with a stable compensation effect as finely as possible while the difficulty of assembling and connecting the multiple compensating heaters 100 is controllable.

[0050] As described above, multiple compensation heaters 100 can be evenly distributed in the insulating adsorption layer 500. Optionally, multiple compensation heaters 100 form a central compensation area and multiple annular compensation areas, and the multiple annular compensation areas are distributed in concentric circles, that is, the central compensation area is a circular structure, and the multiple annular compensation areas are all circular ring structures, and one of the multiple annular compensation areas is arranged outside the central compensation area, and the other annular compensation areas are arranged in sequence in a surrounding manner, so that the multiple compensation heaters 100 form a structure that imitates the wafer, so as to prevent heat waste in the process of providing heat compensation for the wafer, and can improve the accuracy of temperature compensation for the wafer to a certain extent.

[0051] Furthermore, any annular compensation area includes multiple compensation heaters 100 to further reduce the size of any compensation heater 100 and improve the temperature compensation accuracy. In addition, in the process of arranging multiple compensation heaters 100 in any annular compensation area, the multiple compensation heaters 100 in any annular compensation area can include two compensation heaters 100 that are symmetrical and arranged in groups, such as Figure 3 As shown, it can be centrally symmetrical to facilitate the compensation calculation process of multiple compensation heaters 100.

[0052] Optionally, the controller may include a control unit 210 and multiple execution units 220. The control unit 210 may specifically be a PLC (Programmable Logic Controller) or an FPGA (Field Programmable Gate Array). Multiple compensating heaters 100 are arranged in a one-to-one correspondence with multiple execution units 220, and the multiple compensating heaters 100 are respectively connected to corresponding execution units 220, so that execution commands are sent to the multiple compensating heaters 100 using the multiple execution units 220. The execution unit 220 may specifically include a PWM (Pulse Width Modulation) actuator, which has relatively low cost and good noise immunity. More specifically, the PWM actuator may be a relay. The execution unit 220 is capable of receiving the PWM signal sent by the control unit 210 and controlling the opening and closing ratio to control the opening power of the corresponding compensating heater 100. Furthermore, the control unit 210 controls the corresponding compensation heater 100 to output the target power through multiple execution units 220, thereby reducing the number of control units 210, further reducing the overall cost of the electrostatic chuck device, and reducing the difficulty of assembling the controller.

[0053] Alternatively, as Figure 5 As shown, the electrostatic chuck device disclosed in the embodiment of the present application may also include a filter 610. A filter 610 is connected between each compensation heater 100 and the corresponding execution unit 220. The filter 610 is used to filter the connection between the electrostatic chuck device and the external circuit in the radio frequency environment to prevent adverse effects on the external circuit. The external circuit includes a positive power supply and a negative power supply, both of which are connected to the circuit of the electrostatic chuck device to power each compensation heater 100. Of course, the adsorption electrode is also connected to the external circuit, and a power filter box 620 is also provided between the external power supply and the adsorption electrode to provide filtering.

[0054] Based on the electrostatic chuck device disclosed in any of the above embodiments, Figure 7As shown, an embodiment of the present application also discloses a temperature control method, which can be applied to the electrostatic chuck device disclosed in any of the above embodiments to control the working state of the electrostatic chuck device, so that the temperatures at different positions on the wafer carried on the electrostatic chuck device tend to be consistent, thereby improving the process uniformity of the wafer.

[0055] Temperature control methods include:

[0056] S1. Establish a correspondence between process steps and target compensation heaters, wherein the target compensation heaters are the compensation heaters among the multiple compensation heaters except for the compensation heaters corresponding to the locations of the extreme values ​​of the multiple original process results when performing each process step. The above-mentioned original process results are the process results at the locations corresponding to the multiple compensation heaters on the wafer during each process step, while maintaining the heating layer and keeping all compensation heaters turned off. In addition, for the above-mentioned extreme values, when the process result is positively correlated with the temperature at the corresponding location on the wafer, the above-mentioned extreme value is the maximum value. Correspondingly, when the process result is negatively correlated with the temperature at the corresponding location on the wafer, the above-mentioned extreme value is the minimum value.

[0057] To elaborate, during the processing of the wafer, the wafer needs to undergo at least one process step. In any process step, the process result of the wafer is related to the temperature of the wafer, and the process result and the temperature may be positively correlated or negatively correlated. In any case, the temperature of a certain position on the wafer must be related to the process result at that position. Therefore, by detecting the process results at multiple positions on the wafer, the temperature conditions at the corresponding positions on the wafer can be obtained. Among them, the above-mentioned process results can be the etching rate of the wafer, etc. Of course, the process results can also be the deposition rate, etc., which are not limited here.

[0058] As described above, when the wafer is heated using only the heating layer, in theory, the heating efficiency of the heating layer is the same at different locations on the wafer. However, due to various factors, there are still locations on the wafer with different temperatures. Furthermore, there must be at least one location with the highest temperature on the wafer, and the aforementioned at least one location may coincide with at least one of the multiple compensation heaters on the electrostatic chuck device. That is, a compensation heater is provided directly below the location with the highest temperature on the wafer carried on the electrostatic chuck device; or, the location with the highest temperature on the wafer may not be provided with a compensation heater at the location corresponding to the electrostatic chuck device. Therefore, in the process of obtaining the temperature of the wafer (that is, the process result), the temperature (or process result) of multiple locations on the wafer corresponding to the multiple compensation heaters can be measured. In this case, the temperature (or process result) of any compensation heater corresponding to the location on the wafer can be obtained more intuitively.

[0059] Of course, in the process of measuring the temperatures (or process results) of multiple positions in the wafer corresponding to multiple compensation heaters, it is necessary to keep the heating layer in the open state and keep each compensation heater in the closed state, so as to obtain the original value of the process result when the wafer performs the process step, that is, to obtain multiple original process results corresponding one by one to the positions of the multiple compensation heaters.

[0060] During the processing of wafers, in order to ensure a high uniformity of the process results of the wafers, it is necessary to make the temperatures at different positions on the wafer approach the same. Since the compensation heater can only increase the temperature at the corresponding position on the wafer, when using the compensation heater to compensate for the temperature on the wafer, only the compensation heater at the position with relatively low temperature can be operated to compensate for the temperature at the position with low temperature.

[0061] As mentioned above, there must be at least one extreme value among the above-mentioned multiple original process results. Taking the positive correlation between the process results and the temperature as an example, there is at least one maximum value among the above-mentioned multiple original process results. Taking the example of six original process results and one maximum value, it is obvious that when performing this process step, by turning on the five positions with lower temperatures on the wafer except for the aforementioned maximum value, the temperature can be increased within a certain range under the action of the compensation heater, so that the difference between the temperature at the aforementioned five positions and the temperature at the position corresponding to the aforementioned maximum value is reduced, thereby improving the process uniformity of the wafer.

[0062] It should be noted that to prevent the temperatures at the aforementioned five locations from exceeding, or even exceeding significantly, the temperature at the location corresponding to the aforementioned maximum value due to the strong temperature compensation effect of the compensation heater, the heating power of the compensation heater can be relatively low. Furthermore, the heating power of the compensation heater can be determined accordingly based on information such as the difference in process results of the wafers in the process steps, so as to minimize the compensation temperature of the compensation heater from exceeding the temperature at the location corresponding to the aforementioned maximum value by an excessive amount, thereby ensuring relatively high uniformity of process results across the wafers.

[0063] Of course, when there are multiple process steps, the above process can be performed separately for each process step, and the position of the compensation heater that needs to be turned on corresponding to the process step can be obtained, which is recorded as the target compensation heater corresponding to the process step, thereby forming a corresponding relationship between the process step and the target compensation heater.

[0064] Based on the above step S1, the temperature control method disclosed in the embodiment of the present application further includes:

[0065] S2. Obtain the upcoming process step, control the main heaters in the heating layer to turn on, and control the target compensation heaters corresponding to the upcoming process step to turn on according to the corresponding relationship obtained in the above steps.

[0066] As described above, a set of corresponding relationship data can be obtained in advance. Based on this data, the connection between any process step and the target compensation heater can be obtained. Therefore, as long as the process step to be performed is determined, it can be determined based on the above corresponding relationship which one or more compensation heaters are the target compensation heaters. Based on this, when performing the process step, in order to ensure that the process effect at any position on the wafer is relatively good, all the main heaters in the heating layer and the target compensation heater corresponding to the upcoming process step can be turned on. Therefore, under the joint action of the heating layer and the target compensation heater, the temperature at any position on the wafer is made as close to the same as possible, thereby improving the uniformity of the process results of the wafer.

[0067] In the temperature control method disclosed in the above embodiment, as long as there is a situation in which, during a certain process step, the process result of at least one compensation heater and the corresponding area on the wafer is not an extreme value among multiple original process results, then when the process step is subsequently performed, the at least one compensation heater is controlled to be turned on. This may result in the temperature of the area of ​​the wafer corresponding to a certain compensation heater exceeding the extreme value among multiple original process results due to the at least one compensation heater being turned on when the process step is subsequently performed, resulting in the process uniformity on the wafer still not being well achieved.

[0068] Based on this, the above step S2 may include:

[0069] The upcoming process step is obtained, and each main heater in the heating layer is controlled to be turned on. Furthermore, based on the aforementioned correspondence and turn-on ratio, each target compensating heater corresponding to the upcoming process step is controlled to be turned on at a target power. In other words, in this embodiment, when a process step is performed, not only is the target compensating heater corresponding to the upcoming process step controlled based on the aforementioned correspondence, but the target compensating heaters to be turned on can also be turned on at a target power based on the turn-on ratio, thereby further improving the control accuracy of each target compensating heater.

[0070] The above-mentioned opening ratio can be 0.1, 0.2, 1.1, etc., which can be selected according to the actual situation such as the corresponding relationship between the temperature difference and the opening power, and is not limited here. The target power is related to the opening ratio, and the target power is also related to the value to be compensated. In detail, the target power is the product of the opening ratio and the value to be compensated. Among them, the value to be compensated is the difference between the extreme value of the multiple original process results and the original process result corresponding to the target compensation heater. That is, the target power of the target compensation heater is directly related to the process result of the area on the wafer to which it corresponds. In this case, with the combined effect of multiple target compensation heaters, the temperature of the area on the wafer that was originally lower than the temperature at the maximum temperature can be brought closer to the maximum temperature. Even if the temperature of a certain area exceeds the original maximum temperature after being heated by the target compensation heater, since the target power of the target compensation heater is closely related to the original process result of the area corresponding to the target compensation heater, and the original process result is directly related to the temperature, the temperature of the area will not exceed the original maximum temperature by too much after the heat compensation by the target compensation heater. In this way, the temperature uniformity of each area on the wafer can be guaranteed to be higher, thereby improving the uniformity of the process results of the wafer.

[0071] Considering that the temperature of the wafer is affected by many factors, in order to further improve the compensation accuracy of the compensation heater for the temperature at the corresponding position on the wafer, in another embodiment of the present application, optionally, the above step S2 includes:

[0072] The upcoming process step is obtained, and each main heater in the heating layer is controlled to turn on. Based on the above-mentioned correspondence, the value to be compensated, and the influence function, each target compensation heater corresponding to the upcoming process step is controlled to turn on at the target power. That is, in this application, based on the influence function and the value to be compensated, the target power of each target compensation heater to be turned on is further more accurately controlled, so that the target compensation heater operates at the target power, and the process result at the corresponding position can be compensated to be equivalent to or even equal to the extreme value of multiple original process results, further improving the process uniformity of the wafer.

[0073] Of course, to achieve the above purpose, it is necessary to make the reliability of the influence function relatively high. Then, the target compensation heater can be operated at multiple start-up powers respectively, and the process results at the corresponding position on the wafer when the target compensation heater is operated at the corresponding start-up power can be recorded. Any set of data includes the process results and the start-up power. With the support of multiple sets of data, a functional relationship can be obtained, which is the above-mentioned influence function. Moreover, the order of the influence function is related to the number of sets of the aforementioned data. Then, at least two tests can be performed for each target compensation heater, so that the influence function of any target compensation heater is at least a quadratic function, so that the accuracy of the target power obtained based on the influence function is better. Specifically, 10%, 50% and 90% power can be set for any target compensation heater, and the process results at the position corresponding to the target compensation heater are Tn1, Tn2 and Tn3 respectively. The influence function between the output power of the target compensation heater and the process result can be obtained by quadratic function fitting: Pn = k1*T 2 Then, when performing the corresponding process step, the target power for turning on the target compensation heater can be obtained according to the to-be-compensated value of the process result at the position corresponding to the target compensation heater.

[0074] As described above, in the process of performing the process steps using the above-mentioned temperature control method, after the corresponding target compensation heater is controlled to be turned on based on the corresponding relationship established in the above-mentioned step S1, the process results at the positions corresponding to one or more target compensation heaters may exceed (specifically be greater than or less than) the extreme values ​​in multiple original process results, thereby causing new extreme values ​​to appear in the compensated process results, which may cause the process uniformity of the wafer to be possibly not met. Based on this, before using the corresponding relationship established in step S1 to control the operation of the target compensation heater, the established corresponding relationship can be verified first, and only when the verification result meets the requirements, the corresponding target compensation heater can be controlled to be turned on based on the above-mentioned corresponding relationship according to the process steps to be performed.

[0075] In detail, the above step S2 includes:

[0076] When performing a process step, each main heater in the heating layer is turned on, and the corresponding target compensation heater is turned on based on the above correspondence. When the difference between any two of the process results at the positions corresponding to the multiple compensation heaters on the wafer is less than the preset value, the upcoming process step is obtained, and each main heater in the heating layer is controlled to be turned on. According to the above correspondence, the target compensation heater corresponding to the upcoming process step is controlled to be turned on.

[0077] When adopting the above technical solution, the process results of the positions corresponding to the multiple compensation heaters on the wafer are verified in advance by turning on the corresponding target compensation heaters according to the corresponding relationship when performing the process steps. Only when the uniformity of the multiple process results meets the requirements, the corresponding target compensation heaters will be controlled to turn on according to the above correspondence when performing the corresponding process steps later, so as to work together with the heating layer to provide heating for the wafer carried on the electrostatic chuck device, so that the temperature at any position on the wafer is the same or basically the same.

[0078] Accordingly, if during the process steps, the main heaters in the heating layer are turned on, and the corresponding target compensation heaters are turned on based on the corresponding relationship, and the difference between any two of the process results at the positions corresponding to the multiple compensation heaters on the wafer includes a value greater than or equal to the preset value, it is considered that the above-mentioned corresponding relationship may be insufficiently accurate.

[0079] To solve the above situation, the target compensation heater whose difference between the compensated process result and the extreme value of multiple original process results is equal to or greater than the above preset value can be controlled to be in a closed state when performing the corresponding process step. This makes the process result at this position smaller than the extreme value of multiple original process results, but can also improve the process uniformity of the wafer to a certain extent.

[0080] Alternatively, the above embodiment can be used to proportionally control the start-up power of the compensation heater based on the to-be-compensated value of the process result at the position corresponding to the extreme value and the compensation heater. Alternatively, the above embodiment can be used to correspondingly control the start-up power of the compensation heater based on the influence function and the to-be-compensated value of the process result at the position corresponding to the extreme value and the compensation heater. Of course, in the process of adopting these two alternative schemes, it is also possible that when the target compensation heater is turned on with the corresponding target power, the difference between the process result at the position corresponding to one or more target compensation heaters and the extreme value of multiple original process results is equal to or greater than the above preset value. Based on this, the proportional coefficients or various coefficients in the influence function in the above two alternative schemes can be adjusted to obtain new proportional coefficients or influence functions, thereby improving the accuracy of the above two alternative schemes.

[0081] In any of the above embodiments, the sampling of process results at positions on the wafer corresponding to the plurality of compensation heaters is involved. Figure 8 and Figure 3As shown, in actual application, the sampling points (i.e., temperature measurement points) on the sampling device used to provide the sampling function may not correspond one-to-one to the positions of multiple compensation heaters in the already formed electrostatic chuck device, and in order to ensure that the temperature compensation capability of the electrostatic chuck device is relatively strong, it is usually necessary to make the distribution of multiple compensation heaters as uniform as possible.

[0082] Based on this, when obtaining process results at a location on the wafer corresponding to a compensation heater, if a sampling point on the sampling device corresponds exactly to that location, that location can be sampled using that sampling point. If no sampling point on the sampling device corresponds to a location corresponding to a compensation heater, process results at multiple locations surrounding the location corresponding to the compensation heater can be collected and interpolated to obtain the process result at the location corresponding to the compensation heater, reducing the sampling difficulty.

[0083] Specifically, the process result at a location on the wafer corresponding to at least one compensation heater is the average of the process results at multiple other locations on the wafer surrounding the aforementioned location. The process result at the location on the wafer corresponding to the compensation heater is the process result to be measured, and the process result to be measured cannot be obtained through direct measurement; the process results at multiple other locations surrounding the aforementioned location are known process results, and the known process results can be obtained through direct measurement.

[0084] More specifically, if Figure 6 As shown, 6 compensation heaters are provided in the electrostatic chuck device, with the center of the wafer as the zero point of coordinates X and Y, and the coordinates of the center positions of the compensation heaters are (X1, Y1), (X2, Y2) ... (X6, Y6), respectively. The process results of 10 points are checked in the process steps, and the coordinates of these 10 points are (A1, B1), (A2, B2) ... (A10, B10), respectively. Then, according to the above temperature control method, it is necessary to first test the original process results (C1, C2, ..., C10) of these 10 process points when all the compensation heaters are turned off. After that, the process results of the above 10 points can be used by linear interpolation to calculate the process results of the positions on the wafer that are relatively corresponding to the center positions of the 6 compensation heaters. More specifically, Figure 9 The calculation of the point (X1, Y1) indicated by the hollow circle is used as an example to illustrate the specific calculation steps as follows: the horizontal coordinates of the 10 process points are A1-A10, then X1 is between two of them, for example, between A2 and A3; the vertical coordinates of the 10 process points are B1-B10, then Y1 is between two of them, for example, between B3 and B4, then the results of X1 and Y1 are as follows Figure 9As shown in the figure, C1-C5 are the known measured process result data. The coordinates of the other three points around (X1, Y1) except (A3, B3) are (A2, B3), (A2, B4), and (A3, B4). Assuming that the process data of these three points are P1, P2, and P3, the following calculations are performed: P1=(C2+C3) / 2, P2=(P1+P3) / 2, P3=(C3+C4) / 2, then the process data P at (X1, Y1)=(P1+P2+P3+C3) / 4=(3*C2+22*C3+3*C4) / 16.

[0085] Afterwards, find the extreme value of the process result from the above 6 process results (the extreme value is the value of the process result corresponding to the position with the highest temperature, which is not necessarily the actual maximum value, because for some processes, the higher the temperature, the smaller the process result). Assuming that the extreme value is the position corresponding to the first compensation heater, calculate the difference between the process results at the positions corresponding to the remaining 5 compensation heaters and the aforementioned extreme value, respectively, and assume them to be PE1, PE2, ..., PE5. Since the compensation heater can only perform temperature rise compensation, keep the first compensation heater in the off state in the subsequent compensation, and perform temperature compensation on the corresponding positions by turning on the other 5 compensation heaters. During the temperature control process, substitute PE1-PE5 into the influence function relationship Pn=k1*T of each of the above 5 compensation heaters. 2 +k2*T+k3, the output power T1-T5 of the remaining 5 compensation heaters are obtained, and the power data is sent to the control unit to control the PWM actuator to control the corresponding compensation heater to work according to the output power.

[0086] Afterwards, the process results on the wafer are collected again to confirm whether the above control method can meet the uniformity of the wafer. If so, the above control method can be used to control the electrostatic chuck device during the mass production process. If not, a new influence function is obtained by re-taking the value.

[0087] like Figure 10 As shown, by measuring the temperature of multiple positions on the wafer, it can be found that after the above-mentioned control method is used to control the heating process of the electrostatic chuck device, the difference between the temperatures at different positions on the wafer is significantly reduced, and the temperature uniformity on the wafer is significantly improved, thereby ensuring that the process uniformity of the wafer is greatly improved.

[0088] The above embodiments of this application focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0089] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A temperature control method, characterized in that: The temperature control method is applied to an electrostatic chuck device, which includes a device base, a heating layer, and an insulating adsorption layer arranged in sequence from bottom to top, wherein at least two main heaters are provided in the heating layer, and the main heaters are used to heat the wafer carried by the electrostatic chuck device, and the insulating adsorption layer is provided with an adsorption electrode, and the adsorption electrode is used to adsorb the wafer; the electrostatic chuck device also includes a controller, and the insulating adsorption layer is further provided with a plurality of compensation heaters, the plurality of compensation heaters are all insulated from the adsorption electrodes, and the plurality of compensation heaters are all electrically connected to the controller, and the controller is used to control the on or off of each of the compensation heaters, and to control the power of each of the compensation heaters; The temperature control method comprises: S1. Establishing a correspondence between process steps and target compensation heaters, wherein the target compensation heaters are the remaining compensation heaters among the multiple compensation heaters except the compensation heaters corresponding to the positions where the extreme values ​​of the multiple original process results are located when performing each process step; the original process results are process results at positions corresponding to the multiple compensation heaters on the wafer when performing each process step while keeping the at least two main heaters in the heating layer turned on and keeping all the compensation heaters turned off; when the process result is positively correlated with the temperature at the corresponding position on the wafer, the extreme value is the maximum value; when the process result is negatively correlated with the temperature at the corresponding position on the wafer, the extreme value is the minimum value; S2. Acquire the process step to be performed, control each of the main heaters in the heating layer to be turned on, and control each of the target compensation heaters corresponding to the process step to be performed to be turned on according to the corresponding relationship.

2. The temperature control method according to claim 1, characterized in that: The insulating adsorption layer includes a first insulating sublayer, a second insulating sublayer and a third insulating sublayer from bottom to top. The adsorption electrode is arranged between the third insulating sublayer and the second insulating sublayer to form an adsorption sublayer. The multiple compensation heaters are all arranged between the second insulating sublayer and the first insulating sublayer to form a compensation heating layer.

3. The temperature control method according to claim 2, characterized in that: The compensation heater includes a metal resistance heater formed by screen printing, the cable of the compensation heater passes through the device base and the heating layer, and is led out of the device base, and the number of the compensation heaters is greater than or equal to 10 and less than or equal to 100.

4. The temperature control method according to claim 3, characterized in that: The multiple compensation heaters form a central compensation area and multiple annular compensation areas. The multiple annular compensation areas are distributed in concentric circles, and any annular compensation area includes multiple compensation heaters.

5. The temperature control method according to claim 1, wherein: The controller includes a control unit and multiple execution units connected to each other, each compensation heater is connected to the corresponding execution unit, the execution unit includes a PWM actuator, and the control unit controls the corresponding compensation heater to output target power through the multiple execution units.

6. The temperature control method according to claim 5, characterized in that: The electrostatic chuck device further includes a filter, and the filter is connected between each compensation heater and the corresponding execution unit.

7. The temperature control method according to claim 1, characterized in that: The S2 includes: Obtain the upcoming process step, control the main heaters in the heating layer to turn on, and control the target compensation heaters corresponding to the upcoming process step to turn on at the target power according to the corresponding relationship and the turn-on ratio; wherein the difference between the extreme values ​​in the multiple original process results and the original process results corresponding to each target compensation heater is the value to be compensated, and the target power is the product of the turn-on ratio and the value to be compensated.

8. The temperature control method according to claim 1, wherein: The S2 includes: Obtain the upcoming process step, control each of the main heaters in the heating layer to turn on, and control each of the target compensation heaters corresponding to the upcoming process step to turn on at the target power based on the corresponding relationship, the value to be compensated and the influence function; wherein the value to be compensated is the difference between the extreme value in the multiple original process results and the original process result corresponding to each of the target compensation heaters, and the influence function is a functional relationship formed by the process results at the position corresponding to the target compensation heater on the wafer when each of the target compensation heaters works at multiple start-up powers respectively.

9. The temperature control method according to claim 1, wherein: The S2 includes: When performing the process step, each of the main heaters in the heating layer is turned on, and the corresponding target compensation heaters are turned on based on the corresponding relationship. When the difference between any two of the process results at the positions on the wafer corresponding to the multiple compensation heaters is less than a preset value, the upcoming process step is obtained, and each of the main heaters in the heating layer is controlled to be turned on. According to the corresponding relationship, each of the target compensation heaters corresponding to the upcoming process step is controlled to be turned on.

10. The temperature control method according to claim 1, wherein: The process result at a position on the wafer corresponding to at least one of the compensation heaters is an average of process results at a plurality of other positions on the wafer surrounding the position.

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