Wafer heater and wafer adsorption method

Abstract

The invention provides a wafer heater and a wafer adsorption method. The wafer heater comprises an adsorption layer. The adsorption layer is provided with an adsorption surface, the adsorption surface is divided into N adsorption areas, and the N adsorption areas are independently controlled and are used for adsorbing wafers; wherein N is a positive integer greater than or equal to 2. According to the wafer heater provided by the invention, the N independently controlled adsorption areas are arranged on the adsorption surface, so that the adsorption areas on the adsorption surface can independently control the adsorption force and the adsorption sequence corresponding to the adsorption areas according to the shapes of different wafers, so that the degree of freedom of adsorption of the wafers is higher, and the adsorption efficiency is improved. The position of a stress warping area of the wafer is specifically overcome, so that the fitting degree of the wafer and the heating disc is higher, and the heating uniformity of the wafer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing equipment, and in particular to a wafer heater and a wafer adsorption method. Background Art

[0002] In the Chemical Vapor Deposition (CVD) wafer processing chamber, the upper surface of the vacuum adsorption layer is generally flat, and single-zone adsorption is used to fix the wafer on the adsorption layer. However, for 3D flash memory chips, the internal structure of the chip is complex and has many layers, and the thermal expansion coefficients of different materials plated in different processes are different, resulting in thermal stress that causes the wafer to bend and produce a BOW value. It should be noted that the BOW value of the wafer is an important indicator of the wafer, which refers to the curvature of the wafer surface in a free state, that is, the curvature from the center of the wafer to the edge of the wafer. Generally, the smaller the BOW value, the better.

[0003] After the wafer is coated, the introduction of new metal will form internal stress, causing the wafer to have a BOW value, resulting in warping at the edge of the wafer, collapse in the middle of the wafer to form a bowl-shaped structure, or collapse at the edge and bulge in the center. In this case, the suction force of the single zone is not enough to flatten the warp. Once the wafer cannot completely fit the surface of the adsorption layer, it will cause uneven force and the temperature at the center will be significantly higher than that at the edge, affecting the film quality. Summary of the invention

[0004] The purpose of the present invention is to provide a wafer heater and a wafer adsorption method, which ensures the adsorption effect on the wafer so that the wafer is heated evenly, and can correct the wafer during the wafer film forming process, thereby reducing the BOW value of the wafer.

[0005] To achieve the above-mentioned object, in a first aspect, the present invention provides a wafer heater, comprising an adsorption layer;

[0006] The adsorption layer has an adsorption surface, and the adsorption surface is divided into N adsorption areas. The N adsorption areas are controlled separately to adsorb wafers; wherein N is a positive integer greater than or equal to 2.

[0007] The beneficial effect of the wafer heater provided by the present invention is that by arranging N individually controlled adsorption areas on the adsorption surface, the adsorption areas on the adsorption surface can individually control the adsorption force and adsorption sequence corresponding to the adsorption areas according to the shapes of different wafers, so that the adsorption freedom of the wafer is higher, and the position of the stress warping area of ​​the wafer is specifically overcome, so that the wafer and the heating plate are more closely fitted, the uniformity of the heating of the wafer is improved, and the warping area of ​​the wafer can be corrected during the wafer film forming process, reducing the BOW value of the wafer, thereby improving the wafer processing efficiency and increasing production capacity.

[0008] In some embodiments, the adsorption surface is a concave arc surface or a convex arc surface, which has the beneficial effect of being used to adapt to a concave wafer or a convex wafer to make the surface of the wafer flat.

[0009] In some embodiments, the wafer heater further comprises a controller and an exhaust device, wherein the controller is electrically connected to the exhaust device and is used to control the exhaust device so that the exhaust device is used to exhaust each of the adsorption areas individually;

[0010] When the wafer is concave or convex, the controller is used to control the exhaust device to first perform exhaust processing on the adsorption area on the adsorption surface that contacts the wafer.

[0011] In some embodiments, the adsorption force of each adsorption region is the same and is a fixed value.

[0012] In some embodiments, N sealing rings are provided on the adsorption surface;

[0013] Among them, N-1 sealing rings are arranged between two adjacent adsorption areas, and the Nth sealing ring is arranged outside the outermost adsorption area. Its beneficial effect is that by arranging N sealing rings on the adsorption surface, the adjacent adsorption areas are prevented from influencing each other, thereby improving the reliability of independent control of each adsorption area.

[0014] In some embodiments, the adsorption surface is provided with an adsorption groove and an adsorption hole, the adsorption hole is connected to the adsorption groove, and the adsorption holes in each adsorption area are connected to a corresponding exhaust pipeline. The beneficial effect is that by setting independent adsorption grooves in each adsorption area, the adsorption effect on the wafer is guaranteed. In addition, the adsorption holes in each adsorption area are connected to a corresponding exhaust pipeline, thereby realizing the separate control of each adsorption area.

[0015] In some embodiments, the adsorption groove includes a plurality of annular grooves and a plurality of linear grooves having different diameters;

[0016] The plurality of annular grooves are coaxially arranged;

[0017] The linear groove is arranged between adjacent annular grooves and connects adjacent annular grooves;

[0018] A plurality of the adsorption holes are arranged at intervals at the location of the annular groove. The beneficial effect is that a plurality of annular grooves with different diameters are coaxially arranged to ensure the adsorption effect on the wafer.

[0019] In some embodiments, the wafer heater further comprises a plurality of protrusions uniformly arranged on the adsorption surface, the height of the protrusions being the same as the height of the sealing ring, and the protrusions being used to support the wafer. The beneficial effect is that by arranging the protrusions on the adsorption surface, a certain gap is maintained between the wafer and the adsorption surface, and when the wafer is adsorbed on the adsorption surface, the space between the wafer and the adsorption area is divided into N vacuum chambers by the sealing ring, and each vacuum chamber is individually controlled by different exhaust pipelines, so that the adsorption force can be adjusted according to the actual situation to flatten the warped area of ​​the wafer.

[0020] In some embodiments, the wafer heater further comprises a detector and a drive mechanism;

[0021] The detector is arranged on the adsorption surface and is used to detect the flatness of the wafer;

[0022] The driving mechanism is arranged on the adsorption layer;

[0023] A plurality of the protrusions are connected to the driving mechanism;

[0024] The controller is electrically connected to the detector and the driving mechanism;

[0025] When the detector detects that the wafer has a concave area or a convex area, the controller controls the driving mechanism to operate so as to drive the convex part corresponding to the concave area to extend along its axial direction, or drive the convex part corresponding to the convex area to retract along its axial direction. The beneficial effect is that by using the detector to detect the wafer, it is possible to accurately determine which area of ​​the wafer has a concave or convex area, and by controlling the corresponding convex part to adjust its height through the controller, thereby improving the reliability of flattening the warped area of ​​the wafer, and making it more applicable.

[0026] In some embodiments, N independent air extraction channels are provided in the adsorption layer, and N air extraction holes are provided on the surface of the adsorption layer away from the adsorption surface, and the air extraction holes are connected to the corresponding air extraction channels;

[0027] The adsorption hole is communicated with the corresponding air extraction channel.

[0028] In some embodiments, the wafer heater further includes a heating layer connected to the adsorption layer, wherein the heating layer is located on a side away from the adsorption surface and is used to heat the wafer.

[0029] In some embodiments, each of the air extraction channels is symmetrically distributed along the axis of the adsorption layer, and the air extraction hole is arranged at the symmetrical center of the air extraction channel;

[0030] The heating layer is provided with a through hole corresponding to the exhaust hole, the through hole is connected to the exhaust hole, and the through hole is used to connect the exhaust pipeline. Its beneficial effect is that by symmetrically distributing the exhaust channels along the axis of the adsorption layer and arranging the exhaust hole at the symmetrical center of the exhaust channel, the gas flows evenly during the exhaust process, thereby improving the adsorption effect on the wafer.

[0031] In a second aspect, the present invention provides a wafer adsorption method, using the wafer heater to adsorb and bond the wafer, the adsorption method comprising:

[0032] Place the wafer on the adsorption surface;

[0033] Each of the adsorption areas is controlled to adsorb the wafer respectively, so as to correct the wafer.

[0034] The beneficial effect of the wafer adsorption method provided by the present invention is that: by individually controlling the adsorption force and adsorption sequence corresponding to the adsorption area, the adsorption freedom of the wafer is made higher, and the position of the stress warping area of ​​the wafer is overcome in a targeted manner, so that the wafer and the heating plate are more closely fitted, the uniformity of the heating of the wafer is improved, and the warping area of ​​the wafer can be corrected during the wafer film forming process, reducing the BOW value of the wafer, thereby improving the processing efficiency of the wafer and increasing production capacity.

[0035] In some embodiments, the step of controlling each of the adsorption regions to adsorb the wafer includes:

[0036] Detecting the flatness of the wafer to obtain detection data, wherein the detection data includes a wafer with a concave area, a wafer with a convex area, or a normal wafer;

[0037] According to the detection data, when the wafer is a wafer with a concave area or a wafer with a convex area, the adsorption area on the adsorption surface that contacts the wafer is first controlled to perform an exhaust process, and then the remaining adsorption area is controlled to perform an exhaust process. The beneficial effect is that by controlling the adsorption area on the adsorption surface that contacts the wafer to perform an exhaust process first, and then controlling the remaining adsorption area to perform an exhaust process, the effect of the wafer heater on the adsorption and bonding of the wafer is improved, thereby improving the reliability of wafer correction.

[0038] In some embodiments, the heating layer in the wafer heater is coaxially arranged with the adsorption layer;

[0039] The process of respectively controlling each of the adsorption areas to adsorb the wafer to correct the wafer further includes:

[0040] The heating layer is controlled to heat the wafer so that the temperature of the wafer reaches the temperature required by the process. The beneficial effect is that the heating layer heats the wafer so that the temperature of the wafer reaches the temperature required by the process, so that the wafer can be corrected during the film forming process, thereby improving the processing efficiency of the wafer and increasing the production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A front view of a wafer heater according to an embodiment of the present invention;

[0042] Figure 2 A top view of a wafer heater according to an embodiment of the present invention;

[0043] Figure 3 for Figure 2 The enlarged view of point A in the middle;

[0044] Figure 4 A top view of an adsorption layer of an embodiment provided by the present invention;

[0045] Figure 5 A front view of a wafer heater with a convex arc surface as an adsorption surface provided in an embodiment of the present invention;

[0046] Figure 6 A front view of a wafer heater with a concave arc surface as an adsorption surface according to an embodiment of the present invention;

[0047] Figure 7 The present invention provides a flowchart of a wafer adsorption method according to an embodiment of the present invention.

[0048] Reference numerals:

[0049] Adsorption layer 1, adsorption surface 11, adsorption area 111, sealing ring 112, adsorption groove 113, annular groove 1131, linear groove 1132, adsorption hole 114, protrusion 115, exhaust channel 116, exhaust hole 117, heating layer 2, exhaust pipeline 3. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the usual meanings understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Unless otherwise specified, the "connection" described in this article can be a direct connection or an indirect connection, that is, connected through an intermediate.

[0051] In view of the problems existing in the prior art, an embodiment of the present invention provides a wafer heater, referring to Figure 1 and Figure 2 As shown, the wafer heater includes an adsorption layer 1, the adsorption layer 1 is a disc-shaped structure, the upper surface of the adsorption layer 1 is an adsorption surface 11, and the adsorption surface 11 is divided into N adsorption areas 111 at intervals, the adsorption areas 111 are annular areas, the diameters of the N adsorption areas 111 are different, and they are all concentrically arranged on the adsorption surface 11, wherein N is a positive integer greater than or equal to 2. More importantly, the N adsorption areas 111 are individually controlled through the exhaust pipeline.

[0052] In this embodiment, by setting N individually controlled adsorption areas 111 on the adsorption surface 11, the adsorption areas 111 on the adsorption surface 11 can individually control the adsorption force and adsorption sequence of the corresponding adsorption areas 111 according to the shapes of different wafers, so that the adsorption freedom of the wafer is higher, the position of the wafer stress warping area is specifically overcome, the wafer and the heating plate are more closely fitted, and the uniformity of the wafer heating is improved. In addition, by using the wafer heater provided in this embodiment, the correction of the wafer warping area can be achieved when the wafer is heated, and there is no need to heat the wafer and then transfer it to a device specifically for correcting the wafer warping for processing, which improves the processing efficiency of the wafer and thus increases the production capacity.

[0053] Furthermore, N sealing rings 112 are provided on the adsorption surface 11. Among them, N-1 sealing rings 112 are provided between two adjacent adsorption areas 111 to separate different adsorption areas 111 to avoid mutual influence between adjacent adsorption areas 111, and the Nth sealing ring is provided outside the adsorption area of ​​the outermost circle to ensure the sealing of each adsorption area 111 when adsorbing the wafer, and improve the reliability of independent control of each adsorption area 111.

[0054] In this embodiment, the sealing ring 112 is a circular ring-shaped protruding structure protruding from the adsorption surface 11 , and the upper surface of the sealing ring 112 has a high flatness, so as to ensure the sealing effect between the sealing ring 112 and the wafer.

[0055] It should be noted that the adsorption force of each adsorption area 111 is the same and is a fixed value. Therefore, when the number of the adsorption areas 111 changes, the adsorption force of each adsorption area 111 remains unchanged, and the total adsorption force on the adsorption surface 11 changes accordingly. For example, the adsorption force value of each adsorption area 111 remains consistent at F, so the total adsorption force F on the adsorption surface 11 总 =N*F, where N represents the number of the adsorption regions 111 at this time. In some embodiments, the number of the adsorption regions 111 increases by K times, and the total adsorption force F on the adsorption surface 11 is 总 =K*N*F.

[0056] In addition, the total adsorption force F on the adsorption surface 11 is 总 Depends on the pressure difference between the front and back sides of the wafer, and the diameter of the wafer, which satisfies the formula: F 总 =P*A, where P represents the pressure difference between the front and back sides of the wafer, and A represents the area of ​​the wafer. In this embodiment, the total adsorption force F required for adsorbing the wafer can be calculated in advance by using P and A. 总 Then, according to the number of the adsorption areas 111 , the adsorption force F of each adsorption area 111 is calculated.

[0057] For example, in this embodiment, the number of the adsorption regions 111 is 2, and F is calculated based on P and A. 总 After that, the adsorption force F of each adsorption area 111 is F 总 / 2.

[0058] refer to Figure 2 and Figure 3 As shown, in some embodiments, an adsorption groove 113 and an adsorption hole 114 are provided on the adsorption surface 11 , and the adsorption hole 114 is connected to the adsorption groove 113 , and each of the adsorption holes 114 in the adsorption area 111 is connected to a corresponding exhaust pipeline.

[0059] In this embodiment, each adsorption region 111 is provided with independent adsorption grooves 113, and the adsorption grooves 113 are evenly distributed in an annular shape on the adsorption surface 11 to ensure the adsorption effect on the wafer. In addition, the adsorption holes 114 in each adsorption region 111 are connected to corresponding exhaust pipelines, thereby realizing the individual control of each adsorption region 111.

[0060] In addition, the wafer heater further includes a controller and an exhaust device, wherein the controller is electrically connected to the exhaust device and is used to control the operation of the exhaust device. The exhaust device is connected to the corresponding adsorption holes through N exhaust pipelines, and the controller can control the exhaust device to exhaust air in each exhaust pipeline respectively, so as to achieve separate control of the N adsorption areas.

[0061] Specifically, when the wafer is concave or convex, the controller is used to control the vacuum device to first perform vacuum processing on the adsorption area on the adsorption surface that is in contact with the wafer.

[0062] Continue to refer Figure 2 and Figure 3 As shown, in some embodiments, the adsorption groove 113 includes a plurality of annular grooves 1131 and a plurality of linear grooves 1132 with different diameters, the plurality of annular grooves 1131 are coaxially arranged, the linear grooves 1132 are arranged between adjacent annular grooves 1131 and connect adjacent annular grooves 1131, and the plurality of adsorption holes 114 are evenly and spacedly arranged at the positions of the annular grooves 1131, and the exhaust pipeline passes through the adsorption holes 114 for exhausting the adsorption area 111.

[0063] In this embodiment, the annular grooves 1131 in each of the adsorption areas 111 are connected through the linear grooves 1132 , and the exhaust pipeline is used to exhaust the adsorption grooves 113 and the linear grooves 1132 through the adsorption holes 114 so that the adsorption area 111 adsorbs the wafer.

[0064] In some embodiments, the wafer heater also includes a plurality of raised portions 115 evenly arranged on the adsorption surface 11, and the height of the raised portions 115 is the same as the height of the sealing ring 112. The raised portions 115 are used to support the wafer. When the wafer is adsorbed on the adsorption surface 11, the space between the wafer and the adsorption area 111 is divided into N vacuum chambers by the sealing ring 112. Each vacuum chamber is individually controlled by different exhaust pipelines, so that the adsorption force can be adjusted according to actual conditions to flatten the warped area of ​​the wafer.

[0065] In some embodiments, the wafer heater further includes a detector and a driving mechanism, wherein the detector is disposed on the adsorption surface 11 and is used to detect the flatness of the wafer. The driving mechanism is disposed on the adsorption layer 1, and a plurality of the protrusions 115 are connected to the power output end of the driving mechanism, and the power output end can drive each of the protrusions 115 to move individually. The controller is electrically connected to the detector and the driving mechanism, and is used to receive information detected by the detector, and to control the movement of the driving mechanism. When the detector detects that the wafer has a recessed area or a raised area, the controller controls the driving mechanism to operate so as to drive the protrusion 115 corresponding to the recessed area to extend along its axial direction, or to drive the protrusion 115 corresponding to the raised area to retract along its axial direction.

[0066] In this embodiment, the detector may be an image sensor, the driving mechanism may be a lifter, such as a pneumatic lifter, the number of power output ends of the driving mechanism is the same as the number of the protrusions 115, and the controller may independently control each power output end to extend and retract. It is understood that the concave or convex part of the wafer may be at any position, and the surface of the wafer may be detected by using the detector to improve the reliability of the wafer shape judgment, and the controller may control the movement of any power output end of the driving mechanism according to the information detected by the detector to adapt to the adjustment of wafers with different flatness.

[0067] In some embodiments, the wafer may be first inspected by an external image sensor to determine in advance the location of the concave or convex area of ​​the wafer, and then the controller controls the movement of the driving mechanism according to the received detection information to adjust the position of the corresponding protrusion 115 in advance, and finally the wafer is grasped and placed on the adsorption surface 11 by a robot.

[0068] refer to Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, N independent air extraction channels 116 are opened in the adsorption layer 1, and the air extraction channels 116 and the adsorption grooves 113 are distributed and spaced apart along the axial direction of the adsorption layer 1, and N air extraction holes 117 are opened on the surface of the adsorption layer 1 away from the adsorption surface 11, and the air extraction holes 117 are connected to the corresponding air extraction channels 116, and the adsorption holes 114 are connected to the corresponding air extraction channels 116.

[0069] In this embodiment, N is 2, so the number of the adsorption regions 111 and the number of the exhaust channels 116 are both two, the exhaust channels 116 are symmetrically distributed in the adsorption layer 1 along the axis of the adsorption layer 1, the exhaust holes 117 are located at the symmetry center of the exhaust channels 116 and are connected to the exhaust channels 116, and the adsorption holes 114 are symmetrically distributed at both ends of the exhaust channels 116 and are connected to the exhaust channels 116. When the exhaust channels 116 are exhausted through the exhaust holes 117, the gas flows evenly, thereby improving the adsorption effect on the wafer.

[0070] refer to Figure 5 and Figure 6 As shown, in some embodiments, the adsorption surface 11 is a concave arc surface or a convex arc surface, which is used to adapt to wafers of different shapes to make the surface of the wafer flat.

[0071] In this embodiment, when the center of the wafer is high and the edge is low, a wafer heater whose adsorption surface 11 is a concave arc surface is selected, that is, the middle low edge of the adsorption surface 11 is high. At this time, the wafer is placed on the adsorption surface 11, and the wafer will fit with the adsorption surface 11 under the action of vacuum pressure, and the internal stress of the wafer will offset the thermal stress and the coating stress, thereby flattening the warped part of the wafer to ensure the flatness of the wafer. Similarly, when the center of the wafer is low and the edge is high, a wafer heater whose adsorption surface 11 is a convex arc surface is selected, that is, the middle high edge of the adsorption surface 11 is low. At this time, the wafer is placed on the adsorption surface 11, and the wafer will fit with the adsorption surface 11 under the action of vacuum pressure, and the internal stress of the wafer will offset the thermal stress and the coating stress, thereby flattening the warped part of the wafer to ensure the flatness of the wafer.

[0072] It is understandable that when the adsorption surface 11 is a concave arc surface or a convex arc surface, in order to ensure the sealing performance of the sealing ring 112 , the curvature radius of the sealing ring 112 is the same as the curvature radius of the supporting surface formed by the plurality of raised portions 115 on the adsorption surface 11 .

[0073] refer to Figure 1 As shown, in some embodiments, the wafer heater further includes a heating layer 2 connected to the adsorption layer 1 , the heating layer 2 is located on a side away from the adsorption surface 11 , and the heating layer 2 is used to heat the wafer.

[0074] In this embodiment, a heating cavity is provided in the heating layer 2 , and uniformly distributed heating wires are arranged in the heating cavity, and the heating treatment of the wafer is achieved through the heating wires.

[0075] Furthermore, the adsorption layer 1 and the heating layer 2 are disc-shaped structures with the same diameter and are coaxially arranged. The heating layer 2 is provided with a through hole corresponding to the exhaust hole 117, and the through hole is connected to the exhaust hole 117. Each of the through holes is used to be connected to a corresponding exhaust pipeline 3 outside, and the exhaust pipeline 3 is connected to the exhaust device.

[0076] In some embodiments, the exhaust pipeline 3 can be connected to a vacuum pump separately, or each exhaust pipeline 3 can be controlled by switching on and off a diaphragm valve to achieve separate control of each adsorption area 111 .

[0077] In another embodiment of the present invention, a wafer adsorption method is provided, which is implemented by a computer program, and the wafer is adsorbed and bonded by controlling the wafer heater described above, referring to Figure 7 As shown, the adsorption method comprises:

[0078] S701: placing the wafer on the adsorption surface.

[0079] S702: Control each of the adsorption areas to adsorb the wafer respectively, so as to correct the wafer.

[0080] In this step, before the wafer is subjected to adsorption treatment, the flatness of the wafer is first detected to obtain detection data, and the detection data includes a wafer with a recessed area, a wafer with a raised area or a normal wafer, and then the controller controls the operation of the exhaust device according to the detection data. For example, when the wafer detected is a wafer with a recessed area or a wafer with a raised area, the adsorption area on the adsorption surface that contacts the wafer is first controlled to be exhausted, and then the remaining adsorption area is controlled to be exhausted, so that the wafer is completely attached to the adsorption surface to correct the wafer and improve the flatness of the wafer. And in this process, the heating layer is also controlled to heat the wafer so that the temperature of the wafer reaches the temperature required by the process to complete the wafer film forming process.

[0081] In this embodiment, the adsorption force and adsorption sequence corresponding to the adsorption area are individually controlled to make the adsorption freedom of the adsorption surface on the wafer higher, and the position of the stress warping area of ​​the wafer is overcome in a targeted manner, so that the wafer and the heating plate are more closely fitted, thereby improving the uniformity of heating of the wafer, and the warping area of ​​the wafer can be corrected during the wafer film forming process, thereby reducing the BOW value of the wafer, improving the wafer processing efficiency, and increasing production capacity.

[0082] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims

1. A wafer heater, characterized in that: including an adsorption layer; The adsorption layer has an adsorption surface, and the adsorption surface is divided into N adsorption areas. The N adsorption areas are controlled separately to adsorb wafers; wherein N is a positive integer greater than or equal to 2.

2. The wafer heater according to claim 1, characterized in that: The adsorption surface is a concave arc surface or a convex arc surface.

3. The wafer heater according to claim 1, characterized in that: It also includes a controller and an air extraction device, wherein the controller is electrically connected to the air extraction device and is used to control the air extraction device so that the air extraction device is used to extract air from each of the adsorption areas separately; When the wafer is concave or convex, the controller is used to control the exhaust device to first perform exhaust processing on the adsorption area on the adsorption surface that contacts the wafer.

4. The wafer heater according to claim 1, characterized in that: The adsorption force of each adsorption area is the same and is a fixed value.

5. The wafer heater according to claim 3, characterized in that: The adsorption surface is provided with N sealing rings; Among them, N-1 sealing rings are arranged between two adjacent adsorption areas, and the Nth sealing ring is arranged outside the adsorption area of ​​the outermost circle.

6. The wafer heater according to claim 5, characterized in that: The adsorption surface is provided with an adsorption groove and an adsorption hole, the adsorption hole is communicated with the adsorption groove, and the adsorption holes in each of the adsorption areas are connected with a corresponding exhaust pipeline.

7. The wafer heater according to claim 6, characterized in that: The adsorption groove includes a plurality of annular grooves and a plurality of linear grooves with different diameters; The plurality of annular grooves are coaxially arranged; The linear groove is arranged between adjacent annular grooves and connects adjacent annular grooves; A plurality of the adsorption holes are arranged at intervals at the location of the annular groove.

8. The wafer heater according to any one of claims 5 to 7, characterized in that: It also includes a plurality of protrusions evenly arranged on the adsorption surface, the height of the protrusions is the same as the height of the sealing ring, and the protrusions are used to support the wafer.

9. The wafer heater according to claim 8, characterized in that: Also includes a detector and a drive mechanism; The detector is arranged on the adsorption surface and is used to detect the flatness of the wafer; The driving mechanism is arranged on the adsorption layer; A plurality of the protrusions are connected to the driving mechanism; The controller is electrically connected to the detector and the driving mechanism; When the detector detects that the wafer has a recessed area or a raised area, the controller controls the driving mechanism to operate so as to drive the raised portion corresponding to the recessed area to extend along its axial direction, or to drive the raised portion corresponding to the raised area to retract along its axial direction.

10. The wafer heater according to claim 6, characterized in that: N independent air extraction channels are provided in the adsorption layer, and N air extraction holes are provided on the surface of the adsorption layer away from the adsorption surface, and the air extraction holes are connected to the corresponding air extraction channels; The adsorption hole is communicated with the corresponding air extraction channel.

11. The wafer heater according to claim 10, characterized in that: It also includes a heating layer connected to the adsorption layer. The heating layer is located on a side away from the adsorption surface and is used to heat the wafer.

12. The wafer heater according to claim 11, characterized in that: Each of the air extraction channels is symmetrically distributed along the axis of the adsorption layer, and the air extraction hole is arranged at the symmetrical center of the air extraction channel; The heating layer is provided with a through hole corresponding to the air extraction hole, the through hole is communicated with the air extraction hole, and the through hole is used to connect the air extraction pipeline.

13. A wafer adsorption method, characterized in that: The wafer heater according to any one of claims 1 to 12 is used to adsorb and bond the wafer, and the adsorption method comprises: Place the wafer on the adsorption surface; Each of the adsorption areas is controlled to adsorb the wafer respectively, so as to correct the wafer.

14. The adsorption method according to claim 13, characterized in that: The step of respectively controlling each of the adsorption areas to adsorb the wafer includes: Detecting the flatness of the wafer to obtain detection data, wherein the detection data includes a wafer with a concave area, a wafer with a convex area, or a normal wafer; According to the detection data, when the wafer is a wafer with a recessed area or a wafer with a raised area, the adsorption area on the adsorption surface in contact with the wafer is first controlled to perform exhaust treatment, and then the remaining adsorption area is controlled to perform exhaust treatment.

15. The adsorption method according to claim 13, characterized in that: The heating layer in the wafer heater is coaxially arranged with the adsorption layer; The process of respectively controlling each of the adsorption areas to adsorb the wafer to correct the wafer further includes: The heating layer is controlled to heat the wafer so that the temperature of the wafer reaches the temperature required by the process.

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