Electrostatic chuck device and temperature control method

Abstract

The present application discloses an electrostatic chuck device and a temperature control method thereof. The electrostatic chuck device includes an apparatus base, a heating layer, and an insulating adsorption layer for mounting a wafer, which are arranged in this order from bottom to top, an adsorption electrode for adsorbing the wafer is provided in the insulating adsorption layer, at least two main heaters for heating the wafer mounted on the insulating adsorption layer are provided in the heating layer, and an adsorption electrode for adsorbing the wafer is provided in the insulating adsorption layer, the electrostatic chuck device further includes a controller, and a plurality of compensation heaters are further provided in the insulating adsorption layer, each of the compensation heaters is insulated from the adsorption electrode, each of the compensation heaters is electrically connected to the controller, and the controller is used to control the on / off of each compensation heater and the power of each compensation heater.

Description

[Technical field]

[0001] This application is in the field of semiconductor processing, and more particularly, relates to electrostatic chuck apparatus and temperature control methods. [Background technology]

[0002] In the process of processing a semiconductor workpiece (e.g., a wafer) such as a wafer, the workpiece is usually heated using a heater such as an electrostatic chuck to increase the temperature of the entire workpiece in order to improve process efficiency and / or process effect, etc. However, in the actual processing process, for various reasons, there may be unevenness in the temperature of different positions of the workpiece supported by the same heater, resulting in low process uniformity of the workpiece. Summary of the Invention [Problem to be solved by the invention]

[0003] The present application discloses an electrostatic chuck apparatus and a temperature control method that can solve the current problem of low process uniformity on a workpiece due to possible temperature variations at different positions on the workpiece. [Means for solving the problem]

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

[0005] In a first aspect, an embodiment of the present application provides an electrostatic chuck device for semiconductor equipment, comprising, in order from bottom to top, an apparatus base, a heating layer, and an insulating adsorption layer for mounting a wafer, wherein an adsorption electrode for adsorbing the wafer is provided within the insulating adsorption layer, at least two main heaters for heating the wafer mounted on the insulating adsorption layer are provided within the heating layer, an adsorption electrode for adsorbing the wafer is provided within the insulating adsorption layer, and a controller is further provided within the insulating adsorption layer, wherein the insulating adsorption layer further comprises a plurality of compensation heaters, each of the plurality of compensation heaters is provided insulated from the adsorption electrode, each of the plurality of compensation heaters is electrically connected to the controller, and the controller is used to control on / off of each of the compensation heaters and power of each of the compensation heaters.

[0006] In a second aspect, an embodiment of the present application is a temperature control method applied to the electrostatic chuck apparatus for mounting and heating a wafer, comprising: S1, a step of establishing a correspondence between process steps and target compensation heaters, the target compensation heaters being the remaining compensation heaters other than the compensation heaters corresponding to positions of extreme values ​​of multiple original process results among the multiple compensation heaters when performing each of the process steps, the original process results being process results at positions corresponding to the multiple compensation heaters of the wafer when each of the process steps is performed while maintaining the at least two main heaters in the heating layer on and maintaining each of the compensation heaters off, the extreme values ​​being maximum values ​​when the process results show a positive correlation with the temperature of the corresponding positions of the wafer, and the extreme values ​​being minimum values ​​when the process results show a negative correlation with the temperature of the corresponding positions of the wafer; A temperature control method is disclosed, which includes a step S2 of acquiring a process step immediately before execution, controlling each of the main heaters in the heating layer to be turned on, and controlling each of the target compensation heaters corresponding to the process step immediately before execution to be turned on according to the correspondence relationship.

[0007] The present embodiment discloses an electrostatic chuck device applicable to semiconductor equipment, in which an insulating adsorption layer is laminated on a heating layer, the heating layer is laminated on an apparatus base, at least two main heaters in the heating layer can heat a wafer placed on the insulating adsorption layer, and an adsorption electrode in the insulating adsorption layer can adsorb an electrode, thereby ensuring that the wafer can be stably supported on the insulating adsorption layer. In addition, the electrostatic chuck device is provided with a controller, and a plurality of compensation heaters are further provided in the insulating adsorption layer, and the plurality of compensation heaters are all electrically connected to the controller, and the controller can control the on / off of each compensation heater and the power of each compensation heater. Then, by detecting the process results such as the etching rate at different positions of the wafer, the temperature status of the corresponding positions of the wafer can be indirectly obtained from the results of multiple processes, so that when the wafer is heated only by the main heater in the heating layer during some processes, the temperature at different positions of the wafer is not consistent. When the wafer is heated by the main heater during the processes, the controller controls at least one corresponding compensation heater of the electrostatic chuck device to be turned on, and controls the power of the compensation heater in the on state, so that the compensation heater turned on can heat the corresponding position of the wafer, and the temperature of the position can be increased to the maximum temperature value of the wafer (i.e., the maximum or minimum value of the process result of the wafer), so as to ensure that the process uniformity of the wafer is relatively high. And, since the power of the compensation heater is smaller than that of the main heater, the compensation heater is disposed on the insulating adsorption layer with a small distance from the wafer, so that the heat of the compensation heater can be transferred more quickly and more accurately to the area of ​​the wafer corresponding to the compensation heater, and the thermal compensation is provided to the corresponding position of the wafer, and the response speed is faster.

[0008] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and the exemplary embodiments and the description thereof are used to interpret the present application and are not to be construed as unduly limiting the present application. [Brief description of the drawings]

[0009] [Figure 1] 1 is a structural schematic diagram of an electrostatic chuck device according to an embodiment of the present application. [Diagram 2] 1 is a structural schematic diagram of an insulating adsorption portion of an electrostatic chuck device according to an embodiment of the present application. [Diagram 3] FIG. 4 is a schematic diagram showing the distribution of a plurality of compensation heating parts of an electrostatic chuck device according to an embodiment of the present application. [Figure 4] 1 is a structural schematic diagram of an attraction electrode of an electrostatic chuck device according to an embodiment of the present application. [Diagram 5] FIG. 2 is a schematic diagram illustrating the electrical principle of the electrostatic chuck device according to the embodiment of the present application. [Figure 6] 1 is a schematic diagram illustrating the electrical principle of a partial structure of an electrostatic chuck device according to an embodiment of the present application. [Figure 7] 2 is a flowchart of a temperature control method according to an embodiment of the present application. [Figure 8] 4 is a schematic diagram showing the position distribution of a plurality of temperature measurement points on a wafer in a temperature control method according to an embodiment of the present application. [Figure 9] 4 is a schematic diagram showing the relative positions of a plurality of temperature measurement points on a wafer and one compensation heater in a temperature control method according to an embodiment of the present application. FIG. [Figure 10] 5 is a schematic diagram of temperature comparison of a plurality of temperature measurement points on a wafer when a compensation heater is in an on and off state in a temperature control method according to an embodiment of the present application. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to specific embodiments of the present application and corresponding drawings. It is obvious that the described embodiments are only some embodiments of the present application, but not all embodiments. Based on the embodiments of the present application, all other embodiments that a person skilled in the art can obtain without creative labor belong to the protection scope of the present application.

[0011] The technical solutions of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0012] As shown in Figures 1 to 5, the embodiments of the present application disclose an electrostatic chuck device applicable to semiconductor equipment, and use the electrostatic chuck device to place a workpiece such as a wafer, change the temperature of the workpiece such as a wafer, and improve the process efficiency and the quality of the process result. The electrostatic chuck device includes a device base 400, a heating layer 300, and an insulating adsorption layer 500, which are provided from bottom to top. Note that the up-down direction is a vertical direction during normal operation of the electrostatic chuck device, and may be the direction A in Figure 1 more intuitively.

[0013] The insulating adsorption layer 500 is used to mount a wafer, and at least two main heaters are provided in the heating layer 300, and the main heaters can heat the wafer mounted on the insulating adsorption layer 500 to increase the temperature of the wafer, thereby improving the process efficiency and effect of the wafer. The main heaters may specifically include a heating device such as a resistance wire, thereby ensuring that the main heaters have heating capabilities. The number of main heaters may be two, three or more, and the number of main heaters may be determined according to parameters such as the size and shape of each main heater, and is not limited here. The shape of the multiple main heaters may be a fan shape, and together form a 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 rest are all annular structures, and the multiple main heaters are assembled in a nested manner to form the heating area of ​​the heating layer 300, and such a distribution form of the main heaters can control the size of the heating area according to the dimensions of the workpiece such as the diameter of the wafer, and the control accuracy is relatively high. Of course, in addition to the main heater, the heating layer 300 may further include a structure for fixing the main heater, specifically, a molding material such as quartz or ceramic, and multiple main heaters are embedded in the molding material such as quartz or ceramic to form the heating layer 300 with a stable structure.

[0014] An adsorption electrode is provided in the insulating adsorption layer 500, and the adsorption electrode can adsorb the wafer, so that the wafer can be stably placed 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 the actual situation. As shown in FIG. 4, the adsorption electrode is divided into two regions, DC+ and DC-, and the entire adsorption electrode can be a ring structure, or the adsorption electrode can be formed by winding a metal wire several times. And, the adsorption electrode can be formed in a molding material such as quartz or ceramic to form an insulating layer, which on the one hand realizes the purpose of fixing the adsorption electrode, and on the other hand can provide the insulating adsorption layer 500 with insulating ability, and prevents the normal operation of the compensation heater 100 provided in the adsorption insulating layer described later from being adversely affected.

[0015] The electrostatic chuck device according to the embodiment of the present application further includes a controller, and a plurality of compensation heaters 100 are further provided in the insulating adsorption layer 500, and each compensation heater 100 can also heat the insulating adsorption layer 500 during operation, thereby compensating for the temperature of the region where each compensation heater 100 is located and increasing the temperature of the region where each compensation heater 100 is located, and each of the plurality of compensation heaters 100 is provided insulated from the adsorption electrode.

[0016] Specifically, each compensation heater 100 may include a heating device such as a resistance wire, and of course, the specific shape, size, and other parameters thereof may be determined according to actual needs, and are not limited herein. The number of compensation heaters 100 may be determined according to the actual parameters, such as the size and shape of the compensation heater 100 and the size and shape of the insulating adsorption layer 500, and are not limited herein. More specifically, the heating power of each compensation heater 100 may be basically the same, thereby reducing the difficulty of controlling the multiple compensation heaters 100 and improving the temperature control accuracy of the electrostatic chuck device. In addition, the compensation heater 100 may be formed in a molding material, such as quartz or ceramic, in the insulating adsorption layer 500, and the compensation heater 100 and the adsorption electrode are spaced from each other in the thickness direction of the insulating adsorption layer 500 to ensure that each compensation heater 100 can be insulated from the adsorption electrode.

[0017] As a specific embodiment, in the thickness direction of the insulating adsorption layer 500, the positions of the multiple compensation heaters 100 in the insulating adsorption layer 500 may be the same, or the multiple compensation heaters 100 may be evenly distributed so that each compensation heater 100 corresponds to a different region of the insulating adsorption layer 500, and the regions corresponding to the multiple compensation heaters 100 together form the entire surface of the insulating adsorption layer 500. As shown in Fig. 3, the compensation heaters 100 may be distributed as an annular structure, and the compensation heaters 100 in any one annular structure are distributed in the circumferential direction, and the structure and dimensions of the compensation heaters 100 included in each annular structure may be determined according to actual circumstances and are not limited herein.

[0018] In addition, the size of each compensation heater 100 may be relatively small, and in the process of arranging the compensation heaters 100, the distribution of the compensation heaters 100 may be as even as possible, so that the temperature compensation ability of the compensation heaters 100 for the electrostatic chuck apparatus can be improved and comprehensive.

[0019] As described above, the electrostatic chuck apparatus according to the embodiment of the present application includes a controller, and the multiple compensation heaters 100 may all be electrically connected to the controller based on this, so that the controller controls the on / off of each compensation heater 100 and the power of each compensation heater 100. During the operation process of the electrostatic chuck apparatus, a control rule corresponding to the controller may be preset, and the controller may control the compensation heater 100 corresponding to the process step immediately before being executed based on the control rule input in advance according to the specific situation of the process step to be executed.

[0020] More specifically, before the electrostatic chuck apparatus is applied to a mass production process, the heating state of the electrostatic chuck apparatus can be tested in advance. In the test process, only all main heaters in the heating layer 300 are turned on, and all of the compensation heaters 100 are controlled to be in an off state, and the temperatures of a plurality of measurement positions of the electrostatic chuck apparatus are measured, and the plurality of measurement positions correspond one-to-one to the positions of the compensation heaters 100, so as to obtain a plurality of basic data.

[0021] Of course, in the measurement process, since it is relatively difficult to measure temperature data, parameters such as the etching rate at different positions of the workpiece such as a wafer are further measured, and the specific situation of the temperature at that position of the wafer is represented by a parameter such as the etching rate that is directly related to the temperature, that is, the above-mentioned basic data may specifically be the etching rate. In addition, parameters such as the etching rate may be directly proportional to the temperature or inversely proportional to the temperature. For the convenience of the following description, the following takes the etching rate of the wafer as being directly proportional to the temperature as an example. In addition, the multiple measured positions may specifically be the structural center of each compensation heater 100, and of course, the measured positions may be the edges of each compensation heater 100, as long as it is ensured that the measured positions of each compensation heater 100 correspond to each other.

[0022] The magnitudes of the above-mentioned multiple basic data may differ due to various factors such as differences in thermal conductivity conditions at different positions on the electrostatic chuck device. Based on this, the compensation heater 100 corresponding to the basic data is turned on and the compensation heater 100 is used to heat that position, thereby raising 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 basic data with the largest numerical value among the multiple basic data and that basic data, thereby making the difference between the multiple basic data relatively small or making all of the differences between the multiple basic data zero.

[0023] In the above test process, the controller can control the on or off of each compensation heater 100, i.e., the compensation heater 100 corresponding to the highest etching rate of the wafer is turned off, and the compensation heaters 100 corresponding to other positions where the etching rate of the wafer is lower than the highest etching rate are turned on, and these compensation heaters 100 in the on state are used to perform temperature compensation for each position, thereby increasing the temperature of the areas of the wafer corresponding to the multiple compensation heaters 100 in the on state, and further increasing the etching rate thereof.

[0024] When the compensation heater 100 corresponding to the position where the etching rate of the wafer is relatively low is in an ON state, the etching rate of the position can be increased, but the compensation heater 100 in the ON state may increase the temperature of the position more than the temperature of the highest temperature position of the wafer, so that the etching rate of the position becomes the new maximum etching rate position, and the difference of the etching rate of different positions of the wafer may still be large. Based on this, the controller may further control the multiple compensation heaters 100 to operate with different powers, so that the compensation heaters 100 in the ON state can compensate the temperature of the corresponding regions to be close to and even the same as the highest temperature of the wafer, ensuring that the consistency of the etching rates of different positions of the wafer is relatively high.

[0025] The on-power of multiple compensation heaters 100 may be obtained by testing in advance. Specifically, according to the specific process to be performed, the compensation heaters 100 corresponding to the regions of the wafer where the etching rate is less than the maximum value may be turned on with different powers, and the power value closest to the maximum etching rate may be recorded, so that in the mass production process, as long as the process is performed, the controller can control the compensation heaters 100 to be turned on with the power value obtained by the test, so that the temperature and etching rate of the regions of the wafer corresponding to the compensation heaters 100 can correspond to the temperature and maximum etching rate of the wafer, ensuring high process uniformity of the wafer.

[0026] The embodiment of the present application discloses an electrostatic chuck device applicable to semiconductor equipment. In the electrostatic chuck device, an insulating adsorption layer 500 is laminated on a heating layer 300, the heating layer 300 is laminated on an apparatus base 400, at least two main heaters in the heating layer 300 can heat a wafer placed on the insulating adsorption layer 500, and the adsorption electrodes in the insulating adsorption layer 500 can adsorb electrodes, thereby ensuring that the wafer is stably supported by the electrostatic chuck device. In addition, the electrostatic chuck device is provided with a controller, and a plurality of compensation heaters 100 are further provided in the insulating adsorption layer 500, and the plurality of compensation heaters 100 are all electrically connected to the controller, and the controller can control the on / off of each compensation heater 100 and the power of each compensation heater 100. Then, by detecting the process results such as the etching rate at different positions of the wafer, the temperature status of the corresponding positions of the wafer can be indirectly obtained from the process results, so that when the wafer is heated only by the main heater in the heating layer 300 during some processes, the temperature at different positions of the wafer is not consistent. When the wafer is heated by the main heater in the heating layer 300 during the processes, the main heater is used to heat the wafer, and the controller controls at least one corresponding compensation heater 100 of the electrostatic chuck device to be turned on, and controls the working power of the compensation heater 100 in the on state, so that the compensation heater 100 that is turned on can heat the corresponding position of the wafer, and the temperature of the position can be increased to the maximum temperature value of the wafer (i.e., the maximum or minimum value of the process result of the wafer), so as to ensure that the process uniformity of the wafer is relatively high. And, since the power of the compensation heater 100 is smaller than that of the main heater, the compensation heater 100 is arranged on the insulating adsorption layer 500 that is close to the wafer, so that the heat of the compensation heater 100 can be transferred more quickly and more accurately to the area of ​​the wafer corresponding to the compensation heater 100, and the thermal compensation is provided to the corresponding position of the wafer, and the response speed is fast.

[0027] 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, a ceramic material is provided between the compensation heater 100 and the adsorption electrode and outside both of them by integral sintering, and the compensation heater 100 and the adsorption electrode are fixed in the ceramic material by sintering to form the insulating adsorption layer 500.

[0028] In another embodiment of the present application, optionally, as shown in Fig. 2, the insulating adhesive 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 structures, that is, all three are made of insulating materials such as ceramics, and all three are plate-like or layer-like structures, thereby ensuring that devices on opposite sides of any one of the three have the ability to insulate each other.

[0029] The adsorption electrode is then 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 all 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 chucking electrode and the compensation heater 100 are insulated from each other by a molded structure such as the second insulating sub-layer 520. Furthermore, the formed insulating chucking layer 500 has a relatively high reliability of the insulating effect between the chucking electrode and the compensation heater 100. In addition, the first insulating sub-layer 530, the second insulating sub-layer 520, and the third insulating sub-layer 510 are previously prepared, which not only provides a fixed base for the chucking electrode and the compensation heater 100 but also increases the stability of the relative positions of the chucking electrode and the compensation heater 100. In the process of integrally molding the chucking electrode, the compensation heater 100, and the insulating material, the chucking electrode and / or the compensation heater are prevented from shifting from their original positions, and the chucking electrode, particularly the positions of the multiple compensation heaters 100, are maintained at predetermined positions, thereby improving the heating uniformity of the entire electrostatic chuck.

[0030] Specifically, the first insulating sub-layer 530, the second insulating sub-layer 520 and the third insulating sub-layer 510 are all sheet-like structures formed by mixing ceramic particles and adhesive, and then a plurality of compensation heaters 100 may be provided on the first insulating sub-layer 530, and each compensation heater 100 may be specifically an independent electric heating device, and the specific positions of the plurality of compensation heaters 100 may be obtained in advance according to the heating test of the heating layer 300, and the plurality of compensation heaters 100 are as close as possible to the position of the heating layer 300 where the heating temperature of the wafer is relatively low. Of course, the plurality of compensation heaters 100 may be evenly distributed on the first insulating sub-layer 530, and the compensation heaters 100 that need to be turned on during the process are determined according to the specific process type. Then, the second insulating sub-layer 520 is pressed onto the side of the compensation heating layer 550 away from the first insulating sub-layer 530 to cover it, then an adsorption electrode is formed on the second insulating sub-layer 520 by printing or the like, and then the third insulating sub-layer 510 is pressed onto the upper part of the adsorption layer to cover it, thereby forming the whole structure of the insulating adsorption layer 500. Finally, the adsorption electrode and the compensation heater 100 are securely fixed in the first insulating sub-layer 530, the second insulating sub-layer 520 and the third insulating sub-layer 510 by integral sintering, so that the insulating adsorption layer 500 having a stable structure can be formed.

[0031] Optionally, the compensation heater 100 includes a metal resistance heater formed by screen printing, thereby reducing the difficulty of processing multiple compensation heaters. The cable of the compensation heater 100 is pulled out of the device base 400 through the device base 400 and the heating layer 300, thereby protecting the cable of the compensation heater 100 using the device base 400 and the heating layer 300, and the cables of the multiple compensation heaters 100 can be bundled together, thereby reducing the difficulty of arranging the cables of each compensation heater 100. Optionally, the number of compensation heaters 100 can be 10 or more and 100 or less, thereby ensuring that the difficulty of assembling and connecting the multiple compensation heaters 100 is controllable, and providing the heating layer 300 with a compensation action as highly accurate and stable as possible.

[0032] As described above, the multiple compensation heaters 100 may be uniformly distributed in the insulating adsorption layer 500, or optionally, the multiple compensation heaters 100 form a central compensation region and multiple annular compensation regions, which are distributed concentrically, i.e., the central compensation region has a circular structure, the multiple annular compensation regions have annular structures, one of the multiple annular compensation regions is arranged around the outside of the central compensation region, and the remaining annular compensation regions are arranged in sequence around the annular compensation region, i.e., the multiple annular compensation regions are all located around the central compensation region with the center of the central compensation region as the center of the circle, and the multiple compensation heaters 100 form a structure that conforms to the wafer, so that in the process of providing thermal compensation to the wafer, heat waste can be prevented and the accuracy of temperature compensation of the wafer can be improved to a certain extent.

[0033] Any one of the annular compensation regions includes a plurality of compensation heaters 100, thereby further reducing the size of any one of the compensation heaters 100 and improving the temperature compensation accuracy. In addition, in the process of arranging the plurality of compensation heaters 100 in any one of the annular compensation regions, the plurality of compensation heaters 100 in any one of the annular compensation regions may include two compensation heaters 100 arranged symmetrically in a pair, or may be centrally symmetrical as shown in Fig. 3, thereby facilitating the compensation calculation process for the plurality of compensation heaters 100. Also, the central compensation region includes one compensation heater.

[0034] Alternatively, the controller may include a control unit 210 and a plurality of execution units 220, and the control unit 210 may be specifically a PLC (Programmable Logic Controller) or an FPGA (Field Programmable Gate Array), etc. The compensation heaters 100 are provided in one-to-one correspondence with the plurality of execution units 220, and each compensation heater 100 is connected to each execution unit 220 in one-to-one correspondence, whereby the execution units 220 transmit execution commands to the compensation heaters 100, respectively. Alternatively, the execution unit 220 may include a PWM (Pulse Width Modulation) actuator, which is relatively low in cost and has excellent noise resistance. More specifically, the PWM actuator may be a relay, and the execution unit 220 may receive a PWM signal transmitted from the control unit 210 and control the on-power of the corresponding compensation heater 100 by controlling the on-ratio. The control unit 210 then controls the corresponding compensation heaters 100 via the multiple execution units 220 to output the target power, thereby reducing the number of control units 210 installed, which on the one hand further reduces the overall cost of the electrostatic chuck apparatus, and on the other hand also reduces the difficulty of assembling the controller.

[0035] Optionally, as shown in Fig. 5, the electrostatic chuck apparatus according to the embodiment of the present application may further include a filter 610, which is connected between each compensation heater 100 and the corresponding execution unit 220, thereby filtering between the electrostatic chuck apparatus in an RF environment and an external circuit to prevent adverse effects on the external circuit. The external circuit includes a power supply positive pole and a power supply negative pole, both of which are connected to the circuit of the electrostatic chuck apparatus to supply power to each compensation heater 100. Of course, the chucking electrode is also connected to the external circuit, and a power supply filtering box 620 is provided between the external power supply and the chucking electrode to provide a filtering function.

[0036] Based on any one of the electrostatic chuck devices according to the above embodiments, as shown in FIG. 7 , an embodiment of the present application further discloses a temperature control method, which can be applied to any one of the electrostatic chuck devices according to the above embodiments, and controls the operating state of the electrostatic chuck device to make the temperatures at different positions of a wafer placed on the electrostatic chuck device consistent, thereby improving the process uniformity of the wafer.

[0037] The temperature control method includes a step S1 of establishing a correspondence between process steps and target compensation heaters, the target compensation heaters being the remaining compensation heaters other than the compensation heaters corresponding to the positions of the extreme values ​​of the original process results among the multiple compensation heaters when performing each process step, the original process results being process results at positions corresponding to the multiple compensation heaters of the wafer where each process step is performed while maintaining the heating layer and keeping each compensation heater off, and for the extreme values, if the process results show a positive correlation with the temperature of the corresponding position of the wafer, the extreme values ​​are maximum values, and correspondingly, if the process results show a negative correlation with the temperature of the corresponding position of the wafer, the extreme values ​​are minimum values.

[0038] In detail, in the process of processing a wafer, at least one process step must be performed on the wafer, and in any one process step, the process result of the wafer is correlated with the temperature of the wafer, and the process result may show a positive correlation with the temperature, or may show a negative correlation with the temperature. However, in any case, the temperature at any position of the wafer is necessarily correlated with the process result at that position, and therefore, by detecting the process results at multiple positions of the wafer, the temperature status of the corresponding position of the wafer can be obtained. The process result may be the etching rate of the wafer, etc., and of course, the process result may be the deposition rate, etc., and is not limited here.

[0039] As described above, when the wafer is heated only by the heating layer, theoretically, the heating efficiency of the heating layer is the same for different positions on the wafer. However, due to various factors, there are still positions on the wafer with different temperatures. In addition, the wafer should have at least one highest temperature position, and the at least one position may exactly correspond to and overlap with at least one of the multiple compensation heaters in the electrostatic chuck device, that is, the compensation heater may be installed just below the highest temperature position of the wafer placed on the electrostatic chuck device, or the compensation heater may not be installed at the position of the electrostatic chuck device corresponding to the highest temperature position of the wafer. Therefore, in the process of obtaining the temperature of the wafer (i.e., the process result), the temperature (or process result) of multiple positions corresponding to the multiple compensation heaters of the wafer can be measured, and in this case, the temperature (or process result) of any one of the compensation heaters corresponding to the position of the wafer can be obtained more intuitively.

[0040] Of course, in the process of measuring the temperature (or process result) at multiple positions on the wafer corresponding to multiple compensation heaters, it is necessary to maintain the heating layer in an on state and each compensation heater in an off state, thereby obtaining the original value of the process result when the wafer is subjected to the process step, i.e., obtaining multiple original process results that correspond one-to-one to the positions of the multiple compensation heaters.

[0041] During the processing of a wafer, the temperatures at different positions on the wafer need to be consistent to ensure that the process results of the wafer are highly uniform. The compensation heater can only increase the temperature at the corresponding position on the wafer. Therefore, when the compensation heater is used to compensate for the temperature of the wafer, the compensation heater can only be operated at a position with a relatively low temperature to compensate for the temperature at that position.

[0042] As described above, the above-mentioned multiple original process results must have at least one extreme value, and the process results have a positive correlation with temperature. Take the above-mentioned multiple original process results as an example, and there is at least one maximum value. Take the original process results as six and one maximum value as an example. It can be seen that when performing the process step, other compensation heaters than the compensation heater corresponding to the maximum value can be turned on, so that the temperature of the five positions with low temperatures on the wafer can be increased within a certain range through the action of the compensation heaters, and the difference between the temperature of the five positions and the temperature of the position corresponding to the maximum value can be reduced, thereby improving the process uniformity of the wafer.

[0043] In addition, the heating power of the compensation heater can be made relatively small to prevent the temperatures at the five positions from exceeding or significantly exceeding the temperature at the position corresponding to the maximum value due to the strong temperature compensation effect of the compensation heater. Furthermore, the heating power of the compensation heater can be appropriately determined according to information such as the difference in the process results of the wafer in the process steps, thereby preventing the compensation temperature of the compensation heater from significantly exceeding the temperature at the position corresponding to the maximum value as much as possible, and ensuring a relatively high uniformity of the process results of the wafer.

[0044] Of course, when there are multiple process steps, the above process is performed for each process step to obtain the position of the compensation heater that needs to be turned on corresponding to the process step, and the position is marked as the target compensation heater corresponding to the process step, thereby forming a correspondence between the process step and the target compensation heater.

[0045] Based on the above step S1, the temperature control method according to the embodiment of the present application further includes step S2 of obtaining a process step immediately before execution, controlling on each main heater in the heating layer, and controlling on each target compensation heater corresponding to the process step immediately before execution according to the correspondence relationship obtained in the above step.

[0046] As described above, a set of data having a corresponding relationship can be obtained in advance, and the relationship between any one of the process steps and the target compensation heater can be obtained based on the above data, so that when the process step to be performed is determined, any one of the compensation heaters can be obtained as the target compensation heater based on the above corresponding relationship. Based on this, in order to ensure that the process effect at any position on the wafer is relatively good when the process step is performed, all the main heaters in the heating layer and the target compensation heater corresponding to the process step immediately before the process step can be turned on, so that the temperature at any position on the wafer can be made as consistent as possible under the cooperation of the heating layer and the target compensation heater, and the uniformity of the process result of the wafer can be improved.

[0047] In the temperature control method of the above embodiment, during a process step, unless the process result of the area of ​​the wafer corresponding to at least one compensation heater is an extreme value of the multiple original process results, the at least one compensation heater is controlled to be turned on when the process step is performed later. Therefore, by turning on the at least one compensation heater when the process step is performed later, the temperature of the area of ​​the wafer corresponding to a compensation heater will exceed the extreme value of the multiple original process results, and as a result, the process uniformity of the wafer cannot be well achieved.

[0048] Based on this, the above step S2 may include the steps of obtaining the process step immediately before execution, controlling each main heater in the heating layer to be on, and controlling each target compensation heater corresponding to the process step immediately before execution to be on with the target power according to the above correspondence and on-ratio. That is, in this embodiment, when a certain process step is performed, not only the target compensation heater corresponding to the process step to be executed based on the above correspondence, but also the target compensation heater that needs to be on according to the on-ratio can be turned on with the target power, thereby further improving the control accuracy of each target compensation heater.

[0049] The above-mentioned on-ratio may be a value such as 0.1, 0.2, 1.1, etc., and may be selected according to the actual situation such as the correspondence between the temperature difference and the on-power, and is not limited here. The target power is correlated with the on-ratio and also correlated with the compensation value, in particular, the target power is the product of the on-ratio and the compensation value. The compensation value 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 correlated with the process result of the corresponding area of ​​the wafer. In this case, the temperature of the area smaller than the original maximum temperature of the wafer can be made close to the maximum temperature by the cooperation of the multiple target compensation heaters, and even if the temperature of a certain position exceeds the original maximum temperature due to the heating of the target compensation heater, since the target power of the target compensation heater is closely correlated with the original process result of the area corresponding to the target compensation heater, and the original process result is directly correlated with the temperature, the temperature of the position will not greatly exceed the original maximum temperature after thermal compensation by the target compensation heater, and the temperature uniformity of each position of the wafer can be ensured to be higher, thereby improving the uniformity of the process result of the wafer.

[0050] Considering that the temperature of the wafer is affected by various factors, in order to further improve the compensation accuracy of the compensation heater for the temperature of the corresponding position of the wafer, in another embodiment of the present application, the above step S2 optionally obtains the process step just before being executed, controls each main heater in the heating layer to be turned on, and controls each target compensation heater corresponding to the process step just before being executed to be turned on with the target power according to the above corresponding relationship, the compensation target value and the influence function. That is, in the present application, the target power of each target compensation heater that needs to be further turned on is controlled with higher precision according to the influence function and the compensation target value, and the target compensation heater is operated with the target power, and the process result of the corresponding position is compensated until it corresponds to or is equal to the extreme value of the multiple original process results, so as to further improve the process uniformity of the wafer.

[0051] Of course, to achieve the above objective, the reliability of the influence function needs to be relatively high, and the target compensation heaters are operated at different on-powers, respectively, and the process results of the corresponding positions of the wafer when the target compensation heaters are operated at the corresponding on-powers are recorded, and each set of data includes the process results and the on-power, and the functional relationship, which is the influence function, can be obtained with the support of the multiple sets of data. And the series of the influence function is correlated with the number of sets of data, and at least two tests can be performed for each target compensation heater, so that the influence function of any one of the target compensation heaters is at least a quadratic function, and the accuracy of the target power obtained based on the influence function is high. Specifically, the power of any one of the target compensation heaters can be set to 10%, 50% and 90%, and the process results of the positions corresponding to the target compensation heaters are obtained respectively as Tn1, Tn2 and Tn3, and the influence function Pn between the output power of the target compensation heater and the process result is obtained by quadratic function fitting, Pn=k1×T 2 +k2×T+k3 can be obtained. Then, when performing a corresponding process step, the target power of the target compensation heater that needs to be turned on can be obtained according to the compensation target value of the process result at the position corresponding to the target compensation heater.

[0052] As described above, in the process of performing a process step in the above temperature control method, when the corresponding target compensation heater is controlled to be on based on the correspondence relationship established in the above step S1, the process result at the position corresponding to one or more target compensation heaters may exceed the extreme values ​​of the multiple original process results (specifically, be larger or smaller than the extreme values), and as a result, a new extreme value may appear in the compensated process result, and the process uniformity of the wafer may not be met. Based on this, before controlling the operation of the target compensation heater using the correspondence relationship established in step S1, the established correspondence relationship can be verified, and only if the verification result meets the requirements, the corresponding target compensation heater is controlled to be on based on the above correspondence relationship according to the process step to be performed.

[0053] In detail, the above step S2 includes the steps of: before performing the process step immediately before execution, turning on each main heater in the heating layer, and turning on the corresponding target compensation heater based on the above correspondence; and, when the difference between any two of the process results at positions on the wafer corresponding to the multiple compensation heaters is smaller than a predetermined value, obtaining the process step immediately before execution, controlling to turn on each main heater in the heating layer, and controlling to turn on the target compensation heater corresponding to the process step immediately before execution according to the above correspondence.

[0054] When the above technical solution is adopted, when a process step is performed, the corresponding target compensation heater is turned on according to the corresponding relationship, and the process results of the obtained wafer at positions corresponding to the multiple compensation heaters are verified in advance. Only when the uniformity of the multiple process results meets the requirements, when the corresponding process step is performed later, the corresponding target compensation heater is controlled to be turned on according to the above corresponding relationship, and the wafer placed on the electrostatic chuck device is heated in cooperation with the heating layer, so that the temperature of any position on the wafer is the same or approximately the same.

[0055] Correspondingly, 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 correspondence relationship, and if the difference between any two of the process results at positions corresponding to the multiple compensation heaters on the wafer is greater than or equal to a predetermined value, the above correspondence relationship may be inaccurate.

[0056] To solve the above situation, the target compensation heaters whose difference between the compensated process result and the extreme value of the multiple original process results is equal to or greater than the predetermined value may be controlled to be in an off state during the corresponding process step, thereby making the process result at that position smaller than the extreme value of the multiple original process results, but improving the process uniformity of the wafer to a certain extent.

[0057] Alternatively, in the above embodiment, the on-power of the compensation heater may be proportionally controlled based on the extreme value and the compensation target value of the process result at the position corresponding to the compensation heater. Furthermore, in the above embodiment, the on-power of the compensation heater may be correspondingly controlled based on the influence function and the extreme value and the compensation target value of the process result at the position corresponding to the compensation heater. Of course, in the process of adopting these two alternative means, 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 values ​​of the multiple original process results may be greater than the predetermined value, and based on this, various coefficients in the proportional coefficient or influence function in the above two alternative means can be adjusted to obtain new proportional coefficients or influence functions, thereby improving the accuracy of the above two alternative means.

[0058] In any one of the above embodiments, a sampling operation for the process result at positions corresponding to the multiple compensation heaters of the wafer is involved. As shown in Fig. 8 and Fig. 3, in an actual application process, the sampling points (i.e., temperature measurement points) in a sampling device for providing a sampling function may not correspond one-to-one to the positions of the multiple compensation heaters in a molded electrostatic chuck device, and in order to ensure that the temperature compensation ability of the electrostatic chuck device is relatively strong, it is usually necessary to distribute the multiple compensation heaters as evenly as possible.

[0059] Based on this, in the process of acquiring the process result of a position corresponding to any one compensation heater of the wafer, if a sampling point in the sampling device exactly corresponds to the position, the sampling point can be used to provide a sampling operation to the position. If none of the sampling points in the sampling device correspond to the position corresponding to a compensation heater, the process results of multiple positions around the position corresponding to the compensation heater can be collected, and the process result of the position corresponding to the compensation heater can be calculated by an interpolation method, which reduces the difficulty of sampling.

[0060] In particular, the process result at a location on the wafer corresponding to at least one compensation heater is an average of process results at a number of other locations around said location on the wafer, the process result at the location on the wafer corresponding to the compensation heater is a process result to be detected, the process result to be detected cannot be obtained by direct measurement, and the process results at the number of other locations around said location are known process results, the known process results can be obtained by direct measurement.

[0061] More specifically, as shown in Fig. 6, six compensation heaters are provided in the electrostatic chuck device, the center of the wafer is 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, and in the process step, the process results of 10 points are inspected, and the coordinates of these 10 points are (A1, B1), (A2, B2) ... (A10, B10), respectively, in this case, according to the above temperature control method, firstly test the original process results (C1, C2, ..., C10) of these 10 process points when all the compensation heaters are off, and then use the process results of the above 10 points by linear interpolation to calculate the process results of the positions corresponding to the center positions of the six compensation heaters on the wafer. More specifically, the calculation steps are described below by taking the calculation of the point (X1, Y1) indicated by the white circle in Fig. 9 as an example. The abscissas of the ten process points are A1-A10, respectively, and X1 is between two of them, for example, between A2 and A3. The ordinates of the ten process points are B1-B10, respectively, and Y1 is between two of them, for example, between B3 and B4. In this case, the results at X1 and Y1 are shown in FIG. 9, where C1-C5 are the known measured process result data, and the surroundings corresponding to (X1, Y1). The coordinates of the remaining three points other than (A3,B3) are (A2,B3), (A2,B4), and (A3,B4), respectively, and the process data of these three points are P1, P2, and P3, respectively. In this case, the calculations are P1=(C2+C3) / 2, P2=(P1+P3) / 2, and P3=(C3+C4) / 2, and the process data at (X1,Y1) is P=(P1+P2+P3+C3) / 4=(3×C2+22×C3+3×C4) / 16.

[0062] Then, further find the extreme value of the process result from the above six process results (the extreme value is the value of the process result corresponding to the highest temperature position, not necessarily the maximum value of the actual value, because in some processes, the higher the temperature, the smaller the process result) and assume that the extreme value appears at the position corresponding to the first compensation heater, calculate the differences between the process results and the extreme value at the positions corresponding to the remaining five compensation heaters, and call them PE1, PE2, ..., PE5 respectively. Since the compensation heaters can only perform temperature rise compensation, in the subsequent compensation, the first compensation heater is kept off, and the remaining five compensation heaters are turned on to perform temperature compensation for their corresponding positions. In the temperature control process, PE1-PE5 are calculated based on the influence function relationship Pn=k1×T 2 +k2×T+k3 to obtain the output power T1-T5 of each of the remaining five compensation heaters, and send the power data to the control unit to control the operation of the corresponding compensation heater with the output power by controlling the PWM actuator.

[0063] Then, collect the process results of the wafer again to determine whether the above control method can meet the wafer uniformity. If YES, the electrostatic chuck device can be controlled by the above control method in the mass production process. If NO, obtain a new influence function by taking the value again.

[0064] As shown in FIG. 10, the temperatures of multiple positions on the wafer (i.e., the positions of the temperature measurement points) were measured, and after the heating process of the electrostatic chuck device was controlled by the above control method, the temperature difference between different positions on the wafer (i.e., the temperatures at the temperature measurement points) was obviously reduced, which shows that the temperature uniformity of the wafer is obviously improved, and the process uniformity of the wafer is greatly improved.

[0065] In the above embodiments of the present application, the description focuses on the differences between each embodiment, and the different optimization features of each embodiment can be combined to form a more preferred embodiment, unless contradictory, and detailed description is omitted here for the sake of brevity.

[0066] The above is merely an embodiment of the present application, and is not intended to limit the present application. Those skilled in the art may make various modifications and variations to the present application. Any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principles of the present application should be included in the scope of the claims of the present application.

Claims

1. 1. An electrostatic chuck device for semiconductor equipment, comprising: an apparatus base, a heating layer, and an insulating adsorption layer for mounting a wafer, which are provided in this order from bottom to top, an adsorption electrode for adsorbing the wafer is provided within the insulating adsorption layer, at least two main heaters for heating the wafer mounted on the insulating adsorption layer are provided within the heating layer, and the electrostatic chuck device further comprises a controller, a plurality of compensation heaters are further provided within the insulating adsorption layer, each of the plurality of compensation heaters is provided insulated from the adsorption electrode, each of the plurality of compensation heaters is electrically connected to the controller, and the controller is used to control on / off of each of the compensation heaters and power of each of the compensation heaters.

2. 2. The electrostatic chuck device of claim 1, wherein the insulating adsorption layer includes a first insulating sub-layer, a second insulating sub-layer, and a third insulating sub-layer that are provided in this order from bottom to top, the adsorption electrode is provided between the third insulating sub-layer and the second insulating sub-layer to form an adsorption sub-layer, and the compensation heaters are all provided between the second insulating sub-layer and the first insulating sub-layer to form a compensation heating layer.

3. 3. The electrostatic chuck device according to claim 2, wherein the compensation heater includes a metal resistance heater formed by screen printing, and a cable of the compensation heater passes through the device base and the heating layer and is pulled out to the outside of the device base.

4. 4. The electrostatic chuck device according to claim 1, wherein the number of the compensation heaters is 10 or more and 100 or less.

5. 4. The electrostatic chuck device according to claim 3, wherein the compensation heaters form a central compensation region and a plurality of annular compensation regions, the annular compensation regions are distributed concentrically and are all positioned around the central compensation region with the center of the central compensation region as a circular center, each annular compensation region includes a plurality of the compensation heaters, and the central compensation region includes one of the compensation heaters.

6. 2. The electrostatic chuck device according to claim 1, wherein the controller includes a control unit and a plurality of execution units connected to each other, each of the compensation heaters is connected to each of the execution units in a one-to-one correspondence, and the control unit controls the corresponding compensation heater to output a target power via the execution unit.

7. 7. The electrostatic chuck apparatus of claim 6, wherein the actuator comprises a pulse width modulated actuator.

8. 7. The electrostatic chuck device of claim 6, further comprising a filter, the filter being connected between each of the compensation heaters and a corresponding one of the effectors.

9. A temperature control method, which is applied to the electrostatic chuck device according to any one of claims 1 to 8 for mounting and heating a wafer, S1, a step of establishing a correspondence between process steps and target compensation heaters, the target compensation heaters being the remaining compensation heaters other than the compensation heaters corresponding to positions of extreme values ​​of multiple original process results among the multiple compensation heaters when performing each of the process steps, the original process results being process results at positions corresponding to the multiple compensation heaters of the wafer when each of the process steps is performed with the at least two main heaters in the heating layer kept on and each of the compensation heaters kept off, the extreme values ​​being maximum values ​​when the process results show a positive correlation with the temperature of the corresponding positions of the wafer, and the extreme values ​​being minimum values ​​when the process results show a negative correlation with the temperature of the corresponding positions of the wafer; and step S2 of acquiring a process step immediately before execution, controlling each of the main heaters in the heating layer to be on, and controlling each of the target compensation heaters corresponding to the process step immediately before execution to be on in accordance with the correspondence relationship.

10. The S2 is 10. The temperature control method of claim 9, further comprising the steps of: acquiring a process step immediately before execution; controlling each of the main heaters in the heating layer to be on; and controlling each of the target compensation heaters corresponding to the process step immediately before execution to be on with a target power according to the corresponding relationship and on-ratio, wherein the differences between the extreme values ​​of the multiple original process results and the original process results corresponding to each of the target compensation heaters are all compensation target values, and the target power is a product of the on-ratio and the compensation target value.

11. The S2 is 10. The temperature control method of claim 9, further comprising the steps of: acquiring a process step immediately before execution; controlling each of the main heaters in the heating layer to be on; and controlling each of the target compensation heaters corresponding to the process step immediately before execution to be on with a target power according to the correspondence relationship, a compensation object value, and an influence function, wherein the compensation object value is a difference between the extreme value of a plurality of the 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 between the on-power and the process result at a position of the wafer corresponding to the target compensation heater when each of the target compensation heaters operates at a plurality of different on-powers.

12. The S2 is before performing a immediately preceding process step, turning on each of the main heaters in the heating layer and turning on a corresponding target compensation heater based on the correspondence; 10. The temperature control method of claim 9, further comprising: when a difference between any two of the process results at positions of the wafer corresponding to the compensation heaters is smaller than a predetermined value, acquiring a process step immediately before execution, controlling each of the main heaters in the heating layer to be on, and controlling each of the target compensation heaters corresponding to the process step immediately before execution to be on according to the correspondence.

13. 10. The temperature control method of claim 9, 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 around the position on the wafer.

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