Wafer temperature adjustment method

Abstract

The application provides a wafer temperature adjusting method for a wafer processing device, the wafer processing device comprising a reaction cavity, a rotatable susceptor arranged in the reaction cavity, the susceptor comprising opposite upper and lower surfaces, the upper surface carrying a plurality of wafers, the upper surface comprising a plurality of first sub-regions corresponding to the plurality of wafers respectively, the wafer processing device being provided with a temperature adjusting device, the temperature adjusting device comprising an adjusting part fixed relative to the reaction cavity, the adjusting part facing the susceptor and being arranged with a gap from the susceptor, the method comprising: confirming a temperature adjusting reference value based on collected temperature values of the wafers; determining a to-be-adjusted temperature region and a temperature adjusting range of the to-be-adjusted temperature region based on the temperature adjusting reference value; judging whether a normal projection of the adjusting part on the upper surface falls into the to-be-adjusted temperature region, and if yes, controlling the adjusting part to perform temperature adjustment on the to-be-adjusted temperature region based on the temperature adjusting range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a wafer temperature adjusting method. BACKGROUND

[0002] MOCVD (Metal-organic Chemical Vapor Deposition) equipment is mainly used for growing crystal structure for light emitting on wafer surface, such as GaN (Gallium Nitride). The MOCVD equipment comprises a reaction cavity, a susceptor for placing wafer is arranged in the reaction cavity, and the susceptor is rotated around its central axis by a driving device. A heating device is arranged below the susceptor, and the susceptor uniformly transmits the heat radiated by the heating device to the wafer, so that the surface of the wafer reaches the required temperature (usually greater than 1000℃) for process. The temperature of the wafer surface will directly determine the growth rate and quality of the crystal structure. In order to ensure the yield of wafer processing, the temperature of the wafer surface needs to be accurately controlled.

[0003] The susceptor is usually sintered from powder materials (such as graphite, silicon carbide, silicon nitride, etc.). During the sintering process, the density distribution of the powder material is uneven, so that the thermal conductivity of each region of the susceptor inevitably has differences, which will cause large temperature difference between different regions of the same wafer (also known as wafer-in temperature difference) and large temperature difference between different wafers (also known as wafer-to-wafer temperature difference).

[0004] The temperature of the wafer will directly determine the growth rate and quality of the crystal structure. In order to prevent the crystal structure grown on the wafer from having quality defects, maintaining the uniformity of the wafer temperature is an important factor to ensure the process effect. At the same time, in order to ensure the film thickness consistency of batch processing of wafers, the temperature consistency between different wafers is also very important under the premise that each wafer reaches the required temperature.

[0005] The current temperature adjusting method is usually to adjust the temperature in the reaction cavity as a whole, and it is impossible to accurately adjust the temperature of a single wafer, let alone adjust the temperature of the wafer by region. How to provide a temperature adjusting method to adjust the temperature of the corresponding wafer by region without affecting the process in the reaction cavity, and to reduce the wafer-in and wafer-to-wafer temperature difference is a problem to be solved at present. SUMMARY

[0006] The purpose of the present application is to provide a wafer temperature adjusting method, which can independently and in real time adjust the temperature of each wafer without changing the layout of existing elements in the reaction cavity, and can in real time adjust the local temperature of the wafer, thereby improving the temperature consistency between different wafers and the temperature consistency on the wafer surface, and ensuring the yield of wafer processing.

[0007] In order to achieve the above object, the present application provides a wafer temperature adjusting method for a wafer processing device, wherein the wafer processing device comprises a reaction cavity, a rotatable susceptor is arranged in the reaction cavity, the susceptor comprises opposite upper and lower surfaces, the upper surface carries a plurality of wafers, the upper surface comprises a plurality of first sub-zones corresponding to the plurality of wafers, the wafer processing device is provided with a temperature adjusting device, the temperature adjusting device comprises an adjusting part fixed relative to the reaction cavity, the adjusting part is arranged to face the susceptor, and the method comprises the following steps:

[0008] confirming a temperature adjusting reference value based on the collected temperature values of the wafers;

[0009] determining a temperature adjusting range and a temperature adjusting amplitude of a to-be-adjusted region based on the temperature adjusting reference value, wherein the to-be-adjusted region is configured as a first sub-zone having a difference greater than a preset threshold from the temperature adjusting reference value or a local region in the first sub-zone having a difference greater than a preset threshold from the temperature adjusting reference value;

[0010] judging whether a projection of the adjusting part on the upper surface falls on the to-be-adjusted region, and if so, controlling the adjusting part to perform temperature adjustment on the to-be-adjusted region based on the temperature adjusting amplitude.

[0011] Optionally, the adjusting part is configured as a nozzle structure arranged to face the lower surface, and the method of controlling the adjusting part to perform temperature adjustment on the to-be-adjusted region based on the temperature adjusting amplitude comprises the following step: controlling the nozzle to provide cooling gas to the to-be-adjusted region based on the temperature adjusting amplitude.

[0012] Optionally, a flow control element is arranged on a gas pipeline through which the temperature adjusting device delivers the cooling gas to the nozzle structure, so as to control the flow rate or flow volume of the cooling gas flowing from an external cooling gas source into the gas pipeline through the flow control element; the susceptor maintains a uniform rotation speed, and a projection of the nozzle on the upper surface has a first time length from entering to leaving the to-be-adjusted region.

[0013] Optionally, the flow control element is an on-off switch, and the step of controlling the nozzle to provide cooling gas to the to-be-adjusted region comprises the following step: controlling a second time length during which a corresponding on-off switch is in an open state within the first time length; the second time length increases with the increase of the temperature adjusting amplitude.

[0014] Optionally, the flow control element is an on-off switch, and the step of controlling the nozzle to provide cooling gas to the to-be-adjusted region comprises the following step: controlling a duty cycle of a corresponding on-off switch within the first time length; the duty cycle increases with the increase of the temperature adjusting amplitude.

[0015] Optionally, the flow control element is a flow valve; and the controlling the nozzle to provide cooling gas to the temperature-adjusting region comprises: controlling the corresponding flow valve to be in an open state for a third time length within the first time length; the flow valve has a set valve opening degree when it is in the open state; and the third time length increases with the increase of the temperature adjustment range.

[0016] Optionally, the flow control element is a flow valve; and the controlling the nozzle to provide cooling gas to the temperature-adjusting region comprises: controlling the valve opening degree of the corresponding flow valve within the first time length; and the valve opening degree increases with the increase of the temperature adjustment range.

[0017] Optionally, the controlling the nozzle to provide cooling gas to the temperature-adjusting region comprises: the nozzle continuously and stably provides cooling gas to the lower surface; the nozzle is in the orthographic projection of the upper surface from entering to leaving the temperature-adjusting region, the base has a first rotating speed; the nozzle is in the orthographic projection of the upper surface in the non-temperature-adjusting region, the base has a second rotating speed; the second rotating speed is greater than the first rotating speed, and the first rotating speed decreases with the increase of the temperature adjustment range.

[0018] Optionally, the adjusting part is configured as a window heating structure arranged to face the upper surface; and the method of controlling the adjusting part to adjust the temperature of the temperature-adjusting region based on the temperature adjustment range comprises: controlling the window heating structure to deliver heat to the temperature-adjusting region based on the temperature adjustment range.

[0019] Optionally, the temperature adjustment device comprises a blocking piece capable of moving the window heating structure between shielding the window region, partially shielding the window region, and not shielding the window region; and the method of controlling the adjusting part to adjust the temperature of the temperature-adjusting region based on the temperature adjustment range comprises: based on the temperature adjustment range, controlling the size of the area of the window region to control how much heat the window heating structure delivers to the temperature-adjusting region.

[0020] Optionally, the method of confirming the temperature adjustment reference value comprises: setting the minimum value of the average temperatures of all wafers as the temperature adjustment reference value; and the method of determining the temperature-adjusting region and the temperature adjustment range of the temperature-adjusting region based on the temperature adjustment reference value comprises: comparing the difference between the average temperature of a single wafer and the temperature adjustment reference value; if the difference is greater than a preset threshold, the wafer is determined to be a temperature-adjusting wafer, the first sub-region corresponding to the temperature-adjusting wafer is configured as the temperature-adjusting region, and the difference is configured as the temperature adjustment range.

[0021] Optionally, each wafer comprises a plurality of sub-regions, the sub-regions comprising a disc-shaped central region and a plurality of annular regions concentric with the central region and arranged in sequence along the radial direction of the wafer; the method for confirming the temperature adjustment reference value comprises setting the minimum value among the respective average temperatures of the plurality of sub-regions as the temperature adjustment reference value; the method for determining the to-be-adjusted region and the temperature adjustment range of the to-be-adjusted region based on the temperature adjustment reference value comprises comparing the difference between the average temperature of the current sub-region of the current wafer and the temperature adjustment reference value, and if the difference is greater than a preset threshold, determining that the sub-region is a to-be-adjusted region, the local region in the first sub-region corresponding to the to-be-adjusted region is configured as the to-be-adjusted region, and the difference is configured as the temperature adjustment range.

[0022] Optionally, the method for confirming the temperature adjustment reference value comprises setting the maximum value among the respective average temperatures of all wafers as the temperature adjustment reference value; the method for determining the to-be-adjusted region and the temperature adjustment range of the to-be-adjusted region based on the temperature adjustment reference value comprises comparing the difference between the average temperature of the whole single wafer and the temperature adjustment reference value, and if the difference is greater than a preset threshold, determining that the wafer is a to-be-adjusted wafer, the first sub-region corresponding to the to-be-adjusted wafer is configured as the to-be-adjusted region, and the difference is configured as the temperature adjustment range.

[0023] Optionally, each wafer comprises a plurality of sub-regions, the sub-regions comprising a disc-shaped central region and a plurality of annular regions concentric with the central region and arranged in sequence along the radial direction of the wafer; the method for confirming the temperature adjustment reference value comprises setting the maximum value among the respective average temperatures of the plurality of sub-regions as the temperature adjustment reference value; the method for determining the to-be-adjusted region and the temperature adjustment range of the to-be-adjusted region based on the temperature adjustment reference value comprises comparing the difference between the average temperature of the current sub-region of the current wafer and the temperature adjustment reference value, and if the difference is greater than a preset threshold, determining that the sub-region is a to-be-adjusted region, the local region in the first sub-region corresponding to the to-be-adjusted region is configured as the to-be-adjusted region, and the difference is configured as the temperature adjustment range.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] 1) The temperature adjusting method of the present application determines the temperature adjusting range of the upper surface of the susceptor to be adjusted (which can be a first sub-area, or a region in the first sub-area corresponding to the local part of the wafer to be adjusted) based on the temperature values of the wafers collected, and controls the nozzle to provide cooling gas to the temperature adjusting range in real time and independently based on the temperature adjusting range, or controls the window heating structure to deliver heat to the temperature adjusting range in real time and independently based on the temperature adjusting range, so as to adjust the average temperature and local temperature of the wafer, improve the consistency of the temperature between different wafers and the consistency of the wafer surface temperature, and ensure the yield of wafer processing.

[0026] 2) In the present application, the flow rate or flow of the cooling gas flowing out of the nozzle is controlled by the flow control element (on-off switch or flow valve) while the susceptor maintains a uniform rotating speed, and the flow control element is triggered to work based on the position information of the temperature adjusting range, so the adjusting method is simple and diverse (including adjusting the time length of the on-off switch in the open state, the duty cycle of the on-off switch, the time length of the flow valve in the open state, the valve opening of the flow valve, etc.), and is easy to implement. When adjusting the wafer temperature based on the duty cycle of the on-off switch and the valve opening of the flow valve, the temperature change of the temperature adjusting range can also be more uniform.

[0027] 3) In the present application, the rotating speed of the susceptor is controlled based on the position information and the temperature adjusting range of the temperature adjusting range to control the flow of the cooling gas provided by the nozzle to the temperature adjusting range without setting a flow control element in the gas pipeline of the nozzle. Since there is no need to set a high-precision flow control element, the economic cost of wafer processing is reduced.

[0028] 4) In another embodiment of the present application, the area size of the window region can be controlled by setting a blocking piece capable of moving the window heating structure between shielding the window region, partially shielding the window region, and not shielding the window region, so as to control the amount of heat delivered by the window heating structure to the temperature adjusting range, so as to quickly respond to the need for temperature adjustment in another way.

[0029] 5) The present application does not need to change the layout of the existing elements in the reaction chamber, greatly saves the economic cost of wafer processing, and does not interfere with the flow field of the process gas in the reaction chamber. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the description will be briefly introduced below. Obviously, the drawings in the following description are an embodiment of the present application, and those skilled in the art can also obtain other drawings based on these drawings without creative labor:

[0031] Figure 1 is a schematic view of a wafer processing device;

[0032] Figure 2 A schematic view of a wafer processing apparatus according to an embodiment of the present application;

[0033] Figure 3 A schematic view of a nozzle and a wafer from a top view of a susceptor according to an embodiment of the present application;

[0034] Figure 4 A flow chart of a wafer temperature adjusting method according to an embodiment of the present application;

[0035] Figure 5 A schematic view of a nozzle and a wafer from a top view of a susceptor according to another embodiment of the present application;

[0036] Figure 6 A schematic view of a second time duration when a cooling gas is provided to a temperature adjusting region according to an embodiment of the present application;

[0037] Figure 7 A schematic view of a nozzle and a wafer from a top view of a susceptor according to another embodiment of the present application;

[0038] Figure 8 A schematic view of a duty cycle of a switch when a cooling gas is provided to a corresponding first sub-region according to an embodiment of the present application;

[0039] Figure 9 A schematic view of a nozzle and a wafer from a top view of a susceptor according to another embodiment of the present application;

[0040] Figure 10 A schematic view of a third time duration when a corresponding flow valve is in an open state according to an embodiment of the present application,

[0041] Figure 11 A schematic view of a flow rate of a cooling gas from a corresponding nozzle when the cooling gas is provided to a temperature adjusting region according to an embodiment of the present application;

[0042] Figure 12 A schematic view of a rotation speed of a susceptor according to an embodiment of the present application;

[0043] Figure 13 A schematic view of a wafer processing apparatus according to another embodiment of the present application. DETAILED DESCRIPTION

[0044] With reference to the drawings and the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0045] It should be understood that the term "comprising" as used in the specification and the appended claims indicates the presence of the recited features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0046] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0047] It should be further understood that the term "and / or" as used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0048] As used in the present application specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting" depending on the context. Similarly, the phrase "if it is determined" or "if [the described condition or event] is detected" can be interpreted as meaning "upon determining" or "in response to determining" or "upon detecting [the described condition or event]" or "in response to detecting [the described condition or event]" depending on the context.

[0049] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0050] Figure 1Figure 1 is a schematic view of a wafer processing apparatus 1 for depositing or growing a thin film on a wafer W, which includes a reaction chamber 10. The reaction chamber 10 includes a generally cylindrical reaction chamber sidewall 101 and a chamber lid 102. A susceptor 103 is disposed within the reaction chamber 10, and a plurality of wafer support members 104 for supporting the wafer W are disposed on the upper surface of the susceptor 103 in a circumferential direction of the susceptor 103. A heating device is disposed below the susceptor 103, and heat radiated from the heating device is transferred to the wafer support members 104 and the wafer W by the susceptor 103 to achieve a desired temperature (typically greater than 1000 °C) on the wafer surface.

[0051] Process gas is injected into the reaction chamber 10 through a gas inlet 105 in the center of the chamber lid 102 and flows horizontally over the upper surface of the wafer W to be processed. The susceptor 103 is driven to rotate by a rotating shaft 108, and the wafer support members 104 are driven to rotate by the susceptor 103 to make the gas flow environment on the upper surface of the different wafers uniform. The process gas reacts at a certain temperature to deposit a thin film of a desired material on the wafer W, and the temperature on the wafer surface determines the deposition rate of the material. The process gas that has not yet reacted and reaction byproducts are exhausted from the reaction chamber 10 through exhaust ports (not shown) in the reaction chamber sidewall 101. Figure 1

[0052] The heating device typically uses an induction coil 106, and a reciprocating magnetic field in one direction is generated by an alternating current in the induction coil 106. The magnetic field forms a changing electric field on the surface of the susceptor 103, and an eddy current is formed in the susceptor 103 to heat the susceptor 103. The susceptor 103 transfers the generated heat to the wafer W to achieve a desired temperature for the wafer W. The magnetic field generated by the induction coil 106 is not uniformly distributed at the susceptor 103 (this is common knowledge and will not be described here), which results in poor uniformity of the heat distribution of the susceptor 103. Even if the position of the induction coil 106 is adjusted (for example, the distance between adjacent turns of the induction coil 106 is changed), the temperature of the susceptor 103 cannot be independently adjusted by region.

[0053] On the other hand, the susceptor 103 is sintered from a powdered material (such as graphite). During the sintering process, the density of the powdered material is not uniformly distributed, which inevitably results in a large difference in the thermal conductivity of different regions of the susceptor 103, and a large difference in the surface temperature of different wafers W (wafer-to-wafer temperature difference) and a large difference in the thickness of the thin film grown on the surface of different wafers.

[0054] Due to the difference in the distribution of the magnetic field of the induction coil 106 and the difference in the thermal conductivity of different regions of the susceptor 103, when the susceptor 103 rotates, the temperature difference on the surface of the susceptor 103 is large in the radial direction of the susceptor 103. This results in a large temperature difference on the surface of the wafer W in the radial direction of the wafer W and a large number of defects on the surface of the wafer W.

[0055] ​According to the measurement results, the maximum inter-wafer temperature difference between different wafers W and the maximum intra-wafer temperature difference of wafer W typically exceed 5°C, while the desired temperature difference is less than 1°C. The wafer temperature adjustment method of this invention, even when there are large temperature differences in different regions of the substrate 103, can independently adjust the temperature of each wafer W by region without changing the existing component layout within the reaction chamber 10. This improves the uniformity of wafer surface temperature and the temperature consistency between different wafers W, ensuring the yield of wafer processing.

[0056] To achieve the above objectives, the present invention provides a wafer temperature control method, used for such... Figure 2 The wafer processing apparatus 2 shown is a reaction chamber 20, which contains a rotatable base 203 and a heating device located below the base. Figure 2 The heating device in this embodiment is an induction coil 206 arranged in a spiral pattern from the inside out. In other embodiments, the heating device may also be a heating lamp; this is not a limitation of the present invention.

[0057] The base 203 includes an upper surface 2031 and a lower surface 2032. The upper surface 2031 supports a plurality of wafer carrier components 204 for placing wafers W. The wafer carrier components 204 can rotate with the base 203 and also rotate on their own axes. Figure 3 As shown, the base 203 includes a plurality of sector-shaped first partitions 21 corresponding to a plurality of wafers W.

[0058] The wafer processing equipment 2 is equipped with a temperature regulation device, which includes an adjustment part fixed relative to the reaction chamber 20. The adjustment part is disposed facing the base 203 and maintains a gap with the base 203.

[0059] Example 1

[0060] like Figure 2 As shown, the wafer processing apparatus 2 is provided with nozzles 230 facing the lower surface 2032 (the number of nozzles 230 is not limited in this invention). The nozzles 230 are made of a material that does not produce an inductive effect (for example, ceramic material can be used) to prevent damage from electromagnetic induction heating. Each nozzle 230 is connected to an external cooling gas source 207 through an independent gas pipeline 208. In this embodiment, the adjustment unit is the nozzle 230. This temperature adjustment device provides cooling gas to the lower surface 2032 of the base 203 through the nozzle 230 to reduce the temperature of the corresponding area of ​​the lower surface 2032 directly opposite the outlet portion of the nozzle 230, thereby indirectly achieving temperature regulation of the wafer area.

[0061] like Figure 4 As shown, the wafer temperature control method of the present invention includes the following steps:

[0062] S1, confirm the temperature adjustment reference value based on the temperature value of each wafer W collected.

[0063] Based on the temperature field distribution of the wafer W, the wafer W is virtually divided into multiple wafer regions (sub-regions) along the radial direction of the wafer W. In this embodiment, as shown in FIG. 1, the wafer W is virtually divided into a disc-shaped central region W_1 and an edge region W_2 surrounding the outer periphery of the central region. Figure 3 Figure 4 In this embodiment, the number of edge regions W_2 is only an example and is not a limitation of the present application. The radius of the central region W_1 of different wafers W can be different. The multiple sub-regions (wafer regions described above) of each wafer are concentric and arranged in sequence along the radial direction of the wafer.

[0064] In the present application, the temperature adjustment reference value is set according to the temperature distribution of each wafer W collected (including the temperature value of each region of the wafer W). The temperature adjustment reference value can be the minimum value of the average temperature of all wafers.

[0065] S2, determine the temperature adjustment range of the temperature adjustment region located in the first partition 21 based on the temperature adjustment reference value.

[0066] In this embodiment, the difference between the average temperature of the whole single wafer W (the average of the temperature of the central region W_1 and the temperature of the edge region W_2) and the temperature adjustment reference value is compared. If the difference is greater than a preset threshold value (for example, 0.5℃, which is only an example), it is determined that the wafer W needs to be temperature adjusted, and the first partition 21 corresponding to the wafer W needs to be temperature adjusted. The first partition 21 is configured as the temperature adjustment region, and the difference is configured as the temperature adjustment range of the first partition 21.

[0067] In this embodiment, the temperature adjustment of the wafers Wa, Wb, Wc, Wd in Figure 3 is taken as an example. The difference between the average temperature of the whole wafer Wa and the temperature adjustment reference value is less than the preset threshold value, and the difference between the average temperature of the whole wafers Wb, Wc, Wd and the temperature adjustment reference value is 1℃, 3℃, 1.5℃, respectively. The first partitions 21b, 21c, 21d corresponding to the wafers Wb, Wc, Wd are the temperature adjustment regions, and the temperature adjustment ranges of the first partitions 21b, 21c, 21d are 1℃, 3℃, 1.5℃, respectively.

[0068] S3, determine whether the orthographic projection of the nozzle 230 on the upper surface 2031 falls on the temperature adjustment region, and if so, control the nozzle 230 to provide cooling gas to the temperature adjustment region based on the temperature adjustment range.

[0069] ​In the embodiment, the number of the nozzle 230 is one. The top of the nozzle 230 is provided with a plurality of gas outlets 2301 distributed along a first direction parallel to the radial direction of the susceptor. When the susceptor 203 rotates, the orthographic projection of the nozzle 230 on the upper surface 2031 has a movement path relative to the susceptor 203. In the embodiment, the movement path of the nozzle 230 completely covers the first sub-zone 21. In another embodiment, as shown in Figure 5 , the movement path of the nozzle 230 covers half or more than half of the area of the first sub-zone 21 from the inner edge or the outer edge thereof.

[0070] As shown in Figure 2 , each gas pipeline 208 is respectively provided with a flow control element 209, and the control device 251 controls the flow rate or flow volume of the cooling gas flowing from the external cooling gas source 207 into the corresponding gas pipeline 208 through the flow control element 209, so as to realize independent control of the operation of each nozzle 230. The flow control element 209 in the embodiment is a on-off switch.

[0071] In the embodiment, the susceptor 203 always maintains a uniform rotating speed, and the time length for the orthographic projection of the nozzle 230 on the upper surface 2031 to enter and leave the to-be-temperature-adjusted area is a first time length (for example, 10s, which is only an example). In the embodiment, the nozzle 230 provides cooling gas to the to-be-temperature-adjusted area by controlling the second time length during which the on-off switch is in an open state within the first time length. The second time length increases with the increase of the temperature adjustment amplitude.

[0072] Please refer to Figure 3 , with the rotation of the susceptor 203, when the orthographic projection of the nozzle 230 on the upper surface 2031 falls to the first sub-zone 21a, the on-off switch is closed, and the nozzle 230 does not provide cooling gas to the lower surface 2302. When the orthographic projection of the nozzle 230 on the lower surface 2032 falls to the first sub-zones 21b, 21c and 21d, as shown in Figure 6 , the second time lengths during which the on-off switch is in an open state are t1, t2 and t3 respectively, which are 2s, 6s and 3s respectively in the embodiment (which are only examples). The temperature of the first sub-zones 21b, 21c and 21d is adjusted by providing cooling gas to the lower surface 2032 by the nozzle 230, so as to realize independent and real-time adjustment of the temperature of the wafers Wb, Wc and Wd. With the cooperation of the rotation of the wafers Wb, Wc and Wd, the adjustment effect of the nozzle 230 is spread throughout the wafers Wb, Wc and Wd, so that the difference between the average temperature value of the whole wafer Wb, Wc and Wd and the temperature adjustment reference value is less than the above-mentioned preset threshold value, and the consistency of the temperature between different wafers W is improved.

[0073] In another embodiment, the first sub-zone 21a is the to-be-temperature-adjusted area, and two nozzles 230a and 230b are arranged along the circumferential direction of the susceptor. As shown in Figure 7As shown, when the projection of the nozzle 230a on the upper surface 2031 falls within the first sub-zone 21a, the nozzle 230a continuously provides cooling gas to the first sub-zone 21a for the entire first time length. When the projection of the nozzle 230a on the upper surface 2031 is out of the first sub-zone 21a, the difference between the average temperature value of the wafer Wa as a whole and the temperature regulation reference value is still greater than the preset threshold value. As the susceptor 203 rotates, when the projection of the nozzle 230b on the upper surface 2031 falls within the first sub-zone 21a, the nozzle 230b continues to provide cooling gas to the first sub-zone 21a. The second time length of the on-off switch corresponding to the nozzles 230a and 230b is 10s and 5s, respectively (this is only an example). In this embodiment, the nozzles 230a and 230b are triggered to work independently based on the position information of the region to be temperature-regulated (in other embodiments, the number of nozzles can be more than two, which is only an example). Therefore, the same region to be temperature-regulated can be temperature-regulated multiple times within one revolution of the self-rotation of the susceptor 203, effectively improving the regulation efficiency.

[0074] As shown in FIG. 1, the cooling gas outlet of the nozzle 230 is arranged on the lower surface 2032 of the susceptor 203. Figure 2 As shown, in the present application, there is a gap (less than 5mm) between the top surface of the nozzle and the lower surface 2032 of the susceptor. The cooling gas flowing out of the gas outlet flows horizontally along the radial direction of the susceptor to the edge of the susceptor, and then flows into the gas suction port (not shown in the drawing) of the sidewall 201 of the reaction chamber through the gap between the susceptor 203 and the baffle 217, and finally is discharged to the outside of the reaction chamber through the gas outlet. Figure 2 Since the cooling gas does not enter the reaction region above the susceptor, it does not interfere with the flow field of the process gas in the reaction region, and does not affect the processing process of the wafer W. Moreover, the present application does not need to change the layout of the existing elements in the reaction chamber, greatly saving the economic cost of wafer processing.

[0075] Embodiment Two

[0076] Compared with Embodiment One, the difference of the present embodiment is that the cooling gas provided by the nozzle 230 to the region to be temperature-regulated is controlled by controlling the duty cycle of the on-off switch within the first time length. The duty cycle of the on-off switch increases with the increase of the temperature regulation amplitude.

[0077] The on-off switch is intermittently turned on at a frequency H (corresponding to the duty cycle) within the first time length. The total time length of the cooling gas provided by the nozzle 230 to the region to be temperature-regulated within the first time length is adjusted by adjusting the duty cycle of the on-off switch. As shown in FIG. 2, the on-off switch is intermittently turned on at a frequency H within the first time length. Figure 8As shown, when the orthographic projection of nozzle 230 onto the lower surface 2032 falls on the first partitions 21b, 21c, and 21d, the duty cycles of the on / off switches are 0.2, 0.6, and 0.3, respectively, and the total on / off time of the switches is approximately 2s, 6s, and 3s, respectively. This ultimately results in the difference between the overall average temperature of wafers Wb, Wc, and Wd and the temperature adjustment reference value being less than the aforementioned preset threshold. Compared to Embodiment 1, the adjustment method in this embodiment can make the temperature change of the area to be adjusted more uniform.

[0078] Example 3

[0079] In this embodiment, the differences between the average temperature of each of the multiple sub-regions of a single wafer W and the temperature adjustment reference value are compared. If the difference is greater than a preset threshold, the sub-region is determined to be a local part of the wafer requiring temperature adjustment. The region within the first partition 21 corresponding to the local part of the wafer requiring temperature adjustment is configured as the temperature-adjustable region, and the corresponding difference is configured as the temperature adjustment range of the temperature-adjustable region. In a preferred embodiment, the temperature adjustment reference value is set to the minimum value among the average temperatures of the multiple sub-regions.

[0080] like Figure 9 As shown, in this embodiment, wafer W is virtually divided into a central region W_1 and an edge region W_2 (in other embodiments, the number of edge regions W_2 may be more than one; this is only an example). The first partition 21 includes a first fan ring 211 and a second fan ring 212 concentric with it. The first fan ring 211 extends from the outer edge of the first partition 21 to the inner edge of the first partition 21, or the first fan ring 211 extends from the inner edge of the first partition 21 to the outer edge of the first partition 21. The second fan ring 212 is located at the center of the first partition, and the central region W_1 of wafer W falls within the second fan ring 212.

[0081] like Figure 9 As shown, in this embodiment, multiple nozzles are provided along the circumferential direction of the base 203. The movement paths of some nozzles 230 projected onto the upper surface 2031 cover the first fan ring 211, used for temperature regulation of the edge region W_2 of the wafer W. The movement paths of the remaining nozzles 230 projected onto the upper surface 2031 cover the second fan ring 212, used for temperature regulation of the central region W_1 of the wafer W.

[0082] In this embodiment, the temperature adjustment of wafers Wa, Wb, Wc, and Wd is still taken as an example. The temperature difference between the central region W_1 and the edge region W_2 of wafer Wa and the temperature adjustment reference value is less than the preset threshold, so no temperature adjustment is required for wafer Wa. The temperature difference between the central region W_1 of wafer Wb, the edge region W_2 of wafer Wc, and the central region W_1 of wafer Wd and the temperature adjustment reference value all exceed the preset threshold, by 1℃, 3℃, and 1.5℃ respectively. The disk-shaped region corresponding to the central region W_1 of wafer Wb in the first partition 21b, the annular region corresponding to the edge region W_2 of wafer Wc in the first partition 21c, and the disk-shaped region corresponding to the central region W_1 of wafer Wd in the first partition 21d are all regarded as regions to be adjusted. The temperature adjustment ranges of the regions to be adjusted located in the first partitions 21b, 21c, and 21d are 1℃, 3℃, and 1.5℃ respectively.

[0083] In this embodiment, the flow control element 209 is a flow valve. By controlling the corresponding flow valve to be in the open state for a third time during the first time period, the nozzle 230 is controlled to provide cooling gas to the area to be temperature-controlled. When the flow valve is in the open state, it has a set valve opening degree (that is, the cooling gas flowing out of the nozzle 230 has a set flow rate), and the third time period increases with the increase of the temperature adjustment range.

[0084] When base 203 rotates to the position shown Figure 9 As shown, the projection of nozzle 230a onto the upper surface 2031 falls within the first partition 21, and the flow valve corresponding to nozzle 230a is closed, so nozzle 230a does not supply cooling gas to the lower surface 2032. The projections of nozzles 230b, 230c, and 230d onto the upper surface 2031 fall within the temperature-adjustable areas of the first partitions 21b, 21c, and 21d, respectively, and nozzles 230b, 230c, and 230d supply cooling gas to the lower surface 2032. With the coordination of the rotation of wafers Wb, Wc, and Wd, the adjustment effect of nozzles 230b, 230c, and 230d extends to the central region W_1 of wafer Wb, the edge region W_2 of wafer Wc, and the central region W_1 of wafer Wd.

[0085] Figure 10 Regions 1, 2, 3, and 4 in the diagram represent the regions within the first partitions 21a, 21b, 21c, and 21d that correspond to the edge region W_2 of wafer Wa, the center region W_1 of wafer Wb, the edge region W_2 of wafer Wc, and the center region W_1 of wafer Wd, respectively. For example... Figure 10 As shown, the duration for which nozzles 230a, 230b, 230c, and 230d supply cooling gas to regions 1, 2, 3, and 4 (that is, the third duration for which the flow valves corresponding to nozzles 230a, 230b, 230c, and 230d are in the open state) are 0, t1, t2, and t3, respectively, where t2>t3>t1.

[0086] In the embodiment, the temperature of each wafer region can be independently adjusted, which greatly improves the consistency of the wafer surface temperature and ensures the yield of wafer processing.

[0087] In another embodiment, at least two nozzles 230 are arranged in a first direction parallel to the radial direction of the susceptor, which can simultaneously adjust the temperature of multiple wafer regions of the same wafer W, further improving the adjustment efficiency.

[0088] Embodiment Four

[0089] In the embodiment, the flow control element 209 is still a flow valve. Unlike embodiment three, in the embodiment, the valve opening of the corresponding flow valve in the first time length is controlled to realize the control of the nozzle 230 to provide cooling gas to the corresponding temperature-adjusted region. The valve opening of the flow valve increases with the increase of the temperature adjustment range of the temperature-adjusted region.

[0090] The nozzles 230b, 230c, 230d continuously provide cooling gas to the lower surface 2032 in the corresponding first time length. The valve opening of the flow valve corresponding to the nozzles 230c, 230d, 230b decreases in turn. It is easy to understand that the smaller the valve opening, the smaller the flow rate of the cooling gas flowing out of the corresponding nozzle 230. The flow rate of the cooling gas provided to the regions 1, 2, 3, 4 is as shown in the table. Figure 11 Since the temperature of the wafer Wa does not need to be adjusted, the valve opening of the flow valve corresponding to the nozzle 230a is zero, and no cooling gas is provided to the region 1.

[0091] Embodiment Five

[0092] The above-mentioned embodiments one to four all control the flow rate or flow of the cooling gas flowing out of the nozzle 230 by the flow control element 209 (on-off switch or flow valve) under the condition that the susceptor 203 maintains a uniform rotational speed, and trigger the flow control element 209 to work based on the position information of the temperature-adjusted region, to realize the adjustment of the average temperature of the whole wafer W or the temperature of each wafer region. The adjustment method is simple, various and easy to realize.

[0093] In the embodiment, the number of nozzles 230 is 1, and the gas pipeline 208 of the nozzle 230 is not provided with a flow control element 209. The nozzle 230 continuously and stably provides cooling gas to the lower surface 2032 (the nozzle 230 is a normally open nozzle), and the rotational speed of the susceptor 203 is controlled to realize the control of the nozzle 230 to provide cooling gas to the temperature-adjusted region.

[0094] In this embodiment, the base 203 rotates at a first rotational speed during the process of the nozzle 230's orthogonal projection onto the lower surface 2032 from entering to leaving the temperature-controlled area. When the nozzle 230's orthogonal projection onto the lower surface 2032 is outside the temperature-controlled area, the base 203 rotates at a second rotational speed. The second rotational speed is greater than the first rotational speed, and the first rotational speed decreases as the temperature adjustment range increases. In this embodiment, since no flow control element is required, the economic cost of wafer processing is reduced.

[0095] In this embodiment, it is still based on Figure 3 For example, the first three zones, 21b, 21c, and 21d, are designated as temperature-adjustable zones, with temperature adjustment ranges of 1℃, 3℃, and 1.5℃ respectively (this is only an example). The rotation speed of the base 203 is as follows: Figure 12 As shown, when the projection of the nozzle 230 on the upper surface 2031 falls within the first partition 21a, the base 203 has a second rotational speed. When the projection of the nozzle 230 on the upper surface 2031 falls within the first partitions 21b, 21d, and 21c, the rotational speed of the base 203 (which is less than the second rotational speed) decreases sequentially.

[0096] Example 6

[0097] like Figure 13 As shown, unlike embodiments one to five above, the adjustment unit in this embodiment is configured as a window heating structure 230' facing the upper surface 2031. The temperature adjustment device delivers heat to the upper surface 2031 through this window heating structure 230' to increase the temperature of a local area of ​​the upper surface 2031 directly opposite the window area of ​​the window heating structure 230', thereby directly adjusting the temperature of the wafer region. Similar to embodiment one, after determining the temperature-adjustable region of the wafer and the temperature adjustment range, the adjustment unit is controlled to adjust the temperature of the temperature-adjustable region based on the temperature adjustment range. That is, the amount of heat delivered by the window heating structure 230' to the temperature-adjustable region is controlled based on the temperature adjustment range.

[0098] Specifically, the temperature regulating device in this embodiment includes a blocking member (not shown) that allows the window heating structure 230' to move between the shielded window area, the partially shielded window area, and the unshielded window area. More specifically, based on the temperature regulation range, the area size of the window area is controlled to control the amount of heat delivered by the window heating structure 230' to the area to be regulated.

[0099] Unlike Examples 1 to 5, when determining the temperature control reference value, the maximum value among the average temperatures of all wafers is set as the temperature control reference value.

[0100] In this embodiment, the method is to... Figure 3For example, the temperature of the wafer Wc is actually the temperature adjustment reference value, the difference between the average temperature of the wafer Wc as a whole and the temperature adjustment reference value is less than the preset threshold, and the differences between the average temperatures of the wafers Wa, Wb and Wd as a whole and the preset threshold are 3℃, 2℃ and 1.5℃ respectively (i.e., the wafers Wa, Wb and Wd need to be heated by 3℃, 2℃ and 1.5℃ respectively to reach the temperature adjustment reference value). The first sub-zones 21a, 21b and 21d corresponding to the wafers Wa, Wb and Wd are the regions to be temperature-adjusted, and the temperature adjustment ranges of the first sub-zones 21a, 21b and 21d are 3℃, 2℃ and 1.5℃ respectively.

[0101] Specifically, when the normal projection of the window heating structure 230' on the upper surface 2031 is in the region to be temperature-adjusted, the different shielding ratios of the window region are controlled to achieve different temperature adjustment ranges, for example, 30% of the area of the window region is shielded when a temperature adjustment of 3℃ is needed, 60% of the area of the window region is shielded when a temperature adjustment of 2℃ is needed, and so on.

[0102] In another embodiment, the maximum value of the average temperature of each of the plurality of sub-zones can be set as the temperature adjustment reference value when determining the temperature adjustment reference value, so as to adjust the temperature uniformity of the plurality of sub-zones (for details, please refer to Embodiment Three), so as to further take into account the temperature adjustment within the wafer.

[0103] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0104] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wafer temperature control method for a wafer processing apparatus, the wafer processing apparatus comprising a reaction chamber, the reaction chamber having a rotatable base, the base comprising opposing upper and lower surfaces, the upper surface supporting a plurality of wafers, characterized in that, The upper surface comprises a plurality of first sub-zones corresponding to the plurality of wafers, the wafer processing device is provided with a temperature adjusting device, the temperature adjusting device comprises an adjusting part fixed relative to the reaction cavity, the adjusting part is arranged to face the base, and the method comprises: Confirming a temperature adjusting reference value based on the collected temperature values of each wafer; wherein each wafer comprises a plurality of sub-regions, the sub-regions include a disc-shaped central region and a plurality of annular regions concentric with the central region and sequentially arranged along the radial direction of the wafer; the method of confirming the temperature adjusting reference value comprises setting the minimum value of the average temperature of all wafers or the minimum value of the average temperature of a plurality of sub-regions as the temperature adjusting reference value; Determining a to-be-adjusted temperature region and a temperature adjusting range of the to-be-adjusted temperature region based on the temperature adjusting reference value, the to-be-adjusted temperature region is configured as the first sub-zone with a difference greater than a preset threshold from the temperature adjusting reference value or a local region in the first sub-zone with a difference greater than a preset threshold from the temperature adjusting reference value; Judging whether the projection of the adjusting part on the upper surface falls on the to-be-adjusted temperature region, and if so, controlling the adjusting part to adjust the temperature of the to-be-adjusted temperature region based on the temperature adjusting range.

2. The wafer temperature adjustment method of claim 1, wherein, The adjusting part is configured as a nozzle structure arranged to face the lower surface; the method of controlling the adjusting part to adjust the temperature of the to-be-adjusted temperature region based on the temperature adjusting range comprises: controlling the nozzle to provide cooling gas to the to-be-adjusted temperature region based on the temperature adjusting range.

3. The wafer temperature adjustment method of claim 2, wherein, A flow control element is arranged on a gas pipeline through which the temperature adjusting device delivers the cooling gas to the nozzle structure, so as to control the flow rate or flow volume of the cooling gas flowing from an external cooling gas source into the gas pipeline through the flow control element; the base maintains a uniform rotational speed, and the projection of the nozzle on the upper surface has a first time length from entering to leaving the to-be-adjusted temperature region.

4. The wafer temperature adjustment method of claim 3, wherein, The flow control element is an on-off switch, and the control of the nozzle to provide cooling gas to the to-be-adjusted temperature region comprises: controlling a corresponding on-off switch to be in an open state for a second time length within the first time length; the second time length increases with the increase of the temperature adjusting range.

5. The wafer temperature adjustment method of claim 3, wherein, The flow control element is an on-off switch, and the control of the nozzle to provide cooling gas to the to-be-adjusted temperature region comprises: controlling a corresponding on-off switch to be in an open state for a second time length within the first time length; the second time length increases with the increase of the temperature adjusting range.

6. The wafer temperature conditioning method of claim 3, wherein, The flow control element is a flow valve; the control of the nozzle to provide cooling gas to the to-be-adjusted temperature region comprises: controlling a corresponding flow valve to be in an open state for a third time length within the first time length; when the flow valve is in the open state, it has a set valve opening degree; the third time length increases with the increase of the temperature adjusting range.

7. The wafer temperature conditioning method of claim 3, wherein, The flow control element is a flow valve; the control of the nozzle to provide cooling gas to the to-be-adjusted temperature region comprises: controlling a corresponding flow valve to be in an open state for a third time length within the first time length; when the flow valve is in the open state, it has a set valve opening degree; the third time length increases with the increase of the temperature adjusting range.

8. The wafer temperature conditioning method of claim 2, wherein, The control of the nozzle to provide cooling gas to the temperature-adjusting area includes: the nozzle continuously and stably provides cooling gas to the lower surface; the nozzle has a first rotating speed when the orthographic projection of the upper surface is in the temperature-adjusting area; the nozzle has a second rotating speed when the orthographic projection of the upper surface is in the non-temperature-adjusting area; the second rotating speed is greater than the first rotating speed, and the first rotating speed decreases with the increase of the temperature adjustment range.

9. The wafer temperature conditioning method of claim 2, wherein, The method for determining the temperature-adjusting area and the temperature adjustment range based on the temperature-adjusting reference value includes: comparing the difference between the average temperature of the whole single wafer and the temperature-adjusting reference value; if the difference is greater than a preset threshold, the wafer is determined as a temperature-adjusting wafer, the first partition corresponding to the temperature-adjusting wafer is configured as the temperature-adjusting area, and the difference is configured as the temperature adjustment range.

10. The wafer temperature conditioning method of claim 2, wherein, The method for determining the temperature-adjusting area and the temperature adjustment range based on the temperature-adjusting reference value includes: comparing the difference between the average temperature of the current sub-area of the current wafer and the temperature-adjusting reference value; if the difference is greater than a preset threshold, the sub-area is determined as a temperature-adjusting area, the local area in the first partition corresponding to the temperature-adjusting area is configured as the temperature-adjusting area, and the difference is configured as the temperature adjustment range.

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