Wafer and method for adjusting warping degree of wafer

Abstract

The invention discloses a wafer and a method for adjusting the warping degree of the wafer, and the method comprises the steps: providing a wafer which comprises a first surface and a second surface which are opposite to each other; forming a reversible phase change layer on the second surface of the wafer, wherein the reversible phase change layer can generate reversible phase change; according to the warping degree of the wafer, at least part of the region of the reversible phase change layer is controlled to generate phase change, so that the warping degree of the wafer is reduced, the wafer is flatter, errors caused by wafer warping in the subsequent process are reduced, the in-wafer uniformity of the wafer is improved, the yield of the wafer is improved, and the yield of the wafer is improved. And meanwhile, the stress programming and erasing operation of the reversible phase change layer can be carried out by utilizing the characteristics of the reversible phase change layer, so that the stress distribution condition of each region of the second surface of the wafer is adjusted again after the warping degree of the wafer in the subsequent process is changed, and the flatness of the wafer is further improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a wafer and a method for adjusting the warpage of the wafer. Background Art

[0002] In the semiconductor manufacturing process, the degree of wafer warpage has an important impact. Warpage, also known as bending, refers to the phenomenon that the wafer is deformed and uneven in the semiconductor field. In the semiconductor manufacturing process, warpage will affect the quality of the wafer and the progress of the semiconductor manufacturing process. For example, in the photolithography process, if the wafer is warped, its illuminated surface is uneven, which will cause the mask structure to not form a clear image, thereby affecting the accuracy of etching. Due to the high precision of the device structure, it is necessary to control the warpage of the wafer within an acceptable range. However, after the wafer undergoes deposition, grinding and other processes in the process, a large stress will be generated, causing the warpage of the wafer to increase and become out of control. When the wafer is warped, it will present a bowl-shaped warpage state as a whole, that is, the edge of the wafer is higher or lower than its center, forming a bowl shape, so that there is a gap between the edge of the wafer and the horizontal plane, which leads to many problems. Summary of the invention

[0003] The purpose of the present application is to provide a wafer and a method for adjusting the warpage of the wafer, so as to solve the technical problem of wafer warpage in the prior art.

[0004] In a first aspect, the present application provides a method for adjusting the warpage of a wafer, the method comprising:

[0005] Providing a wafer, the wafer comprising a first side and a second side opposite to each other;

[0006] A reversible phase change layer is formed on the second surface of the wafer, wherein the reversible phase change layer can undergo a reversible phase change; and according to the warpage of the wafer, at least a partial area of ​​the reversible phase change layer is controlled to undergo a phase change.

[0007] In some embodiments, the reversible phase change layer includes Ge-Sb-Te material.

[0008] In some embodiments, the at least partial region includes one or more reversible phase change zones, and the reversible phase change zones are capable of undergoing a reversible phase change. The controlling the phase change of at least a partial region of the reversible phase change layer further includes: performing heat treatment on at least one reversible phase change zone on the reversible phase change layer according to the warping of the wafer so as to cause the at least one reversible phase change zone to undergo a phase change.

[0009] In some embodiments, the thermally treating the reversible phase change region further comprises: adjusting a processing configuration of the thermal treatment of the at least one reversible phase change region according to a warpage of the wafer.

[0010] In some embodiments, the processing configuration includes: a first configuration, the first configuration includes a heat treatment temperature of the at least one reversible phase change region being lower than 650 degrees Celsius, and the heat treatment time being greater than 5 minutes, and the at least one reversible phase change region is transformed from an amorphous phase to a crystalline phase under the first configuration; or

[0011] The second configuration includes heat treatment temperature of the at least one reversible phase change zone being higher than 650 degrees Celsius and heat treatment time being less than 2 minutes, and the at least one reversible phase change zone is transformed from a crystalline phase to an amorphous phase under the second configuration.

[0012] In some embodiments, the heat treatment includes any one of laser annealing, plasma beam annealing, or electron beam annealing.

[0013] In some embodiments, processing at least a portion of the reversible phase change layer further includes: applying a current to the at least one reversible phase change region according to the warpage of the wafer.

[0014] In some embodiments, applying current to at least one of the reversible phase change zones further includes: adjusting the magnitude of the current applied to the at least one reversible phase change zone and / or the power-on time according to the warpage of the wafer.

[0015] In some embodiments, applying current to the at least one reversible phase change zone further includes: applying an electric pulse signal to the at least one reversible phase change zone, and the pulse width and amplitude of the electric pulse signal applied when the at least one reversible phase change zone transforms from the crystalline phase to the amorphous phase are greater than the pulse width and amplitude of the electric pulse signal applied when the at least one reversible phase change zone transforms from the amorphous phase to the crystalline phase.

[0016] In some embodiments, two adjacent reversible phase change regions are isolated from each other by an insulating region.

[0017] In a second aspect, the present application further provides a wafer, comprising a first surface and a second surface opposite to the first surface, wherein a reversible phase change layer is formed on the second surface, and the reversible phase change layer can undergo a reversible phase change. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 A schematic diagram of the structure of a wafer in the related technology of the present application is shown;

[0020] Figure 2A schematic flow chart of a method for adjusting the circular warpage of a wafer provided in an embodiment of the present application is shown;

[0021] Figure 3 A schematic diagram of the structure of a wafer provided in an embodiment of the present application is shown;

[0022] Figure 4 Another schematic diagram of the structure of a wafer provided in an embodiment of the present application is shown;

[0023] Figure 5 Another structural schematic diagram of a wafer provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present application. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present application.

[0025] Various structural schematic diagrams according to embodiments of the present application are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0026] In the context of the present application, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In general, such as Figure 1 As shown in FIG. 1 , when the wafer 100 is warped, it will present a bowl-shaped warping state as a whole, that is, the warping will cause the edge of the wafer 100 to be higher than its center, forming a bowl shape, so that a gap is generated between a part of the wafer 100 and the horizontal plane. Usually, we can adjust the warpage of the wafer 100 by depositing a stress film. For example, we can Figure 1 A film with compressive stress, such as a silicon nitride film, is deposited on the warped wafer 100, and the stress generated by the stress film is used to reduce the warpage of the wafer 100. The warpage refers to the warpage value of the wafer 100 in different directions or positions, that is, the farthest distance from the wafer 100 to the reference plane in a certain direction or position of the wafer 100.

[0030] However, we found that the warpage of the wafer 100 at different positions and directions has obvious differences, that is, the wafer 100 will produce a saddle-shaped warpage. At this time, the deposition of the stress film can improve the overall warpage of the wafer 100, but it is impossible to control the warpage at different positions and directions, and the wafer 100 still has obvious warpage differences. Therefore, the above-mentioned method of relying solely on the deposition of the stress film is difficult to ensure that the warpage of the wafer 100 at various positions and directions can be kept within the specified specification range. And the stress film layer deposition to adjust the stress is usually one-time. After adjusting the warpage of the wafer 100, other processes are performed on the wafer 100, which may cause the warpage of the wafer 100 to change again. At this time, the warpage of the wafer 100 needs to be readjusted. The re-deposition of the stress film layer, on the one hand, causes the thickness of the wafer 100 to be too thick, and the stress transfer is weakened, and the secondary warpage adjustment cannot be performed. On the other hand, it makes the warpage adjustment method of the wafer 100 too complicated, which increases the processing time and cost of the wafer 100.

[0031] In order to overcome the above problems, an exemplary embodiment of the present application provides a method for adjusting the warpage of a wafer, providing a wafer, wherein the wafer includes a first surface and a second surface relative to each other; a reversible phase change layer is formed on the second surface of the wafer, and the reversible phase change layer can undergo a reversible phase change; according to the warpage of the wafer, at least a partial area of ​​the reversible phase change layer is controlled to undergo a phase change.

[0032] Figure 2 1 is a flow chart of a method 110 for adjusting the warpage of a wafer according to the present embodiment. The method 110 for adjusting the warpage of a wafer according to the present embodiment may include:

[0033] S101, providing a wafer, wherein the wafer comprises a first surface and a second surface opposite to each other; forming a reversible phase change layer on the second surface of the wafer, wherein the reversible phase change layer can undergo a reversible phase change;

[0034] S102, controlling at least a partial region of the reversible phase change layer to undergo phase change according to the warpage of the wafer.

[0035] In step S101, the reversible phase change layer 11 can undergo a reversible phase change, which means that the reversible phase change layer 11 or at least a partial region of the reversible phase change layer 11 can be repeatedly converted between a first phase and a second phase, for example, from the first phase to the second phase and then from the second phase to the first phase, or from the second phase to the first phase and then from the first phase to the second phase, and the first phase and the second phase are two different crystalline phases, for example, the first phase can be a crystalline phase and the second phase is an amorphous phase.

[0036] Figure 3 FIG. 1 shows a schematic diagram of the structure of a wafer 100 provided in an embodiment of the present application. Figure 3 As shown, the wafer 100 in the embodiment of the present application may include: a substrate 10. The material of the substrate 10 may be undoped single crystal silicon, single crystal silicon doped with impurities, silicon-on-insulator (SOI) or single crystal silicon with an epitaxial layer, etc. A functional layer 12 is formed on the substrate 10. The side where the functional layer 12 is located is the first side of the wafer 100, and the side opposite to the first side of the wafer 100 is the second side of the wafer 100. A reversible phase change layer 11 is formed on the second side of the wafer 100, and the reversible phase change layer 11 can undergo a reversible phase change.

[0037] The reversible phase change layer 11 may be formed on the second surface of the wafer 100 by deposition, for example, by physical vapor deposition, chemical vapor deposition or atomic layer deposition.

[0038] In actual application, the second surface of the wafer 100 is usually used as a supporting surface and is not used to form functional devices. Therefore, forming the reversible phase change layer 11 on the second surface of the wafer 100 will not affect the subsequent process, nor will it affect the function of the wafer 100. The purpose of forming the reversible phase change layer 11 on the second surface of the wafer 100 in step S101 is to subsequently process at least a portion of the reversible phase change layer 11 to change the phase change of at least a portion of the reversible phase change layer 11, thereby changing the stress of at least a portion of the reversible phase change layer 11, so that the wafer 100 deforms with the phase change of the reversible phase change layer 11, thereby selectively adjusting the warpage of the wafer 100 in one direction or multiple directions.

[0039] In some embodiments, the reversible phase change layer 11 may include a material that can produce a reversible phase change, such as a Ge—Sb—Te phase change material.

[0040] In some embodiments, the Ge-Sb-Te phase change material may include (GeTe) a Sb b Te c . For example, 3<a≤10, 1≤b≤4, 1≤c≤4, a, b, c are natural numbers. Since GeTe accounts for a large proportion in Ge-Sb-Te material, the melting point of the material tends to be higher. Increasing the proportion of GeTe requires more energy to form an amorphous phase, thereby improving the thermal stability of the reversible phase change layer 11, making it less likely to undergo phase change during wafer processing, resulting in a change in the warpage of the wafer 100.

[0041] Furthermore, the material of the reversible phase change layer 11 may also include at least one of the elements Ti, Cr, Mn, Fe, Co, Ni, Cu, Se, Zr, Nb, Mo, Ru, Ag, In, Sn, Ta, W, or Au. These elements can form an alloy with the Ge-Sb-Te phase change material, which can increase the melting point and crystallization temperature of the reversible phase change layer 11, improve the thermal stability of the reversible phase change layer 11, and make the reversible phase change layer 11 less likely to undergo phase change during the processing of the wafer 100, resulting in a change in the warpage of the wafer 100.

[0042] In step S102, at least a portion of the reversible phase change layer 11 is processed to control the phase change of at least a portion of the reversible phase change layer 11. This is to change the phase change state of at least a portion of the reversible phase change layer 11, thereby changing the stress state of at least a portion of the reversible phase change layer 11, thereby selectively adjusting the warping of the wafer 100 in one direction or multiple directions.

[0043] At the same time, the characteristics of the reversible phase change layer 11 can be used to program and erase the stress of the reversible phase change layer 11, so that when the warpage of the wafer 100 changes in the subsequent process, the stress distribution of multiple areas on the second surface of the wafer 100 can be readjusted to further improve the flatness of the wafer 100.

[0044] In some embodiments, at least a portion of the region includes one or more reversible phase change zones 111 , and controlling the phase change of at least a portion of the reversible phase change layer 11 further includes: heat treating at least one reversible phase change zone 111 on the reversible phase change layer 11 according to the warpage of the wafer 100 .

[0045] After heat treatment, the reversible phase change zone 111 can be transformed from the first phase to the second phase, or from the second phase to the first phase, thereby changing the stress condition of the reversible phase change zone 111 and transferring the stress to the wafer 100, thereby selectively adjusting the warpage of the wafer 100 in one direction or multiple directions.

[0046] In some embodiments, the first phase of the reversible phase change region 111 may be a crystalline phase, and the second phase may be an amorphous phase.

[0047] Figure 4 A schematic diagram showing another structure of the wafer 100 provided in an embodiment of the present application is shown.

[0048] In some embodiments, reference Figure 4 If it is necessary to transform the reversible phase change zone 111 from the crystalline phase to the amorphous phase, the reversible phase change zone 111 can be heat-treated so that the reversible phase change material in the reversible phase change zone 111 is melted and then rapidly cooled. The reversible phase change zone 111 after the heat treatment transforms from the crystalline phase to the amorphous phase. The microstructure of the reversible phase change zone 111 after the heat treatment transforms from a regular lattice structure to a long-range disordered structure, and the distance between atoms becomes larger, thereby increasing the volume of the reversible phase change zone 111. Compressive stress is generated between the reversible phase change zone 111 after the heat treatment and the adjacent region 112 that has not been heat-treated. The generated compressive stress can be transmitted to the substrate 10, thereby changing the stress condition of the wafer 100 and reducing the warpage of the wafer. Similarly, when it is necessary to make the reversible phase change zone 111 undergo a reverse phase change (i.e., from an amorphous phase to a crystalline phase), a heat treatment at a lower temperature than that used when the reversible phase change zone 111 changes from the crystalline phase to the amorphous phase is used, so that the reversible phase change zone 111 is heated up and then slowly cooled. The material of the reversible phase change zone 111 can change from the amorphous phase back to the crystalline phase, thereby eliminating the previously adjusted stress and enabling the warping of the wafer 100 to be readjusted to adapt to the latest warping of the wafer 100.

[0049] In some embodiments, heat treating the reversible phase change region 111 may further include: determining a processing configuration for heat treating at least one reversible phase change region 111 according to the warpage of the wafer 100. It is understandable that the warpage of the wafer 100 at different positions or directions may be different, and thus the processing configurations for heat treating different reversible phase change regions 111 are different.

[0050] For example, when after some processes, the wafer 100 will only have positive warpage in the X direction and the Y direction, then the processing configuration of the heat treatment can be determined according to the warpage of the wafer 100 in the X direction and the Y direction. The processing configuration of the heat treatment may include the temperature of the heat treatment, the time of the heat treatment, the position, shape and area of ​​the heat-treated area on the wafer 100, etc. In this way, the processing configuration of the heat treatment can be determined only by measuring the warpage of the wafer 100 in the X direction and the Y direction, thereby improving the efficiency and accuracy of adjusting the warpage of the wafer 100.

[0051] In addition, a database can be established by using the correspondence between the warpage of the wafer 100 in the X direction and the Y direction and the processing configuration of the heat treatment. In this way, after obtaining the warpage of the wafer 100 in the X direction and the Y direction, the corresponding processing configuration is directly retrieved from the database, which is suitable for adjusting the warpage of the wafer 100 in batches on the production line.

[0052] However, when it is uncertain in which direction the wafer 100 is warped or when the wafer 100 is warped in a complex manner (for example, the wafer 100 is warped in a saddle shape), the deformation direction and deformation amount of the wafer in different regions cannot be known based only on the warpage of the wafer 100 in the X and Y directions, and therefore the heat treatment strategy cannot be determined. At this time, it is necessary to obtain the warpage of the wafer 100 at different positions and directions. The processing configuration of the heat treatment of the reversible phase change layer 11 can be more accurately determined by the warpage of the wafer 100 at different positions and directions.

[0053] In some embodiments of the present application, after providing the wafer 100, a strain distribution map of the wafer 100 is obtained. The strain distribution map can clearly show the deformation direction, deformation amount and other deformation conditions of different regions of the wafer 100, so that the warpage of the wafer 100 in different directions and at different positions can be determined. According to the strain distribution map, the warpage of the wafer 100 in different positions and directions can be determined. Therefore, obtaining the strain distribution map of the wafer 100 can more accurately determine the processing configuration of the heat treatment of different regions of the wafer 100. It can be understood that the method of determining the warpage of the wafer 100 in different directions and at different positions through the strain distribution map of the wafer 100 is only an example, but the present application is not limited thereto. Those skilled in the art can obtain the warpage of the wafer 100 in different directions by other existing or future means, which will not be repeated here.

[0054] In some embodiments, a processing configuration for the thermal treatment may include a first configuration and a second configuration.

[0055] The first configuration may include heat treating the at least one reversible phase change region 111 at a temperature lower than 650 degrees Celsius for a time greater than 5 minutes, and the at least one reversible phase change region 111 may transform from an amorphous phase to a crystalline phase under the first configuration.

[0056] The second configuration may include heat treating the at least one reversible phase change region 111 at a temperature higher than 650 degrees Celsius for a time shorter than 2 minutes, and the at least one reversible phase change region 111 may transform from a crystalline phase to an amorphous phase under the second configuration.

[0057] The heat treatment in the present application may include high-energy beam heat treatment, which refers to directing a high-energy beam to act on the surface of a material to cause physical, chemical or phase structural changes, thereby achieving the purpose of modifying the surface of the material. The heat source of the high-energy beam can generally include a laser, an electron beam, an ion beam, an electric spark, etc. In the present application, high-energy beam heat treatment includes any one of laser annealing, ion beam annealing or electron beam annealing. The beam spot size of the high-energy beam is small, and local heat treatment can be performed on a micro-area. At the same time, a larger area heat treatment can also be performed by superposition scanning method, so the heat treatment area can be adjusted arbitrarily according to needs; high-energy beam heat treatment has good controllability, and the temperature and holding time of the heat treatment can be adjusted arbitrarily.

[0058] In the embodiment of the present application, laser annealing is performed by using a processing configuration that uses different heat treatments on different regions of the reversible phase change layer 11. Laser annealing is a relatively mature application, and the heat treatment depth, heat treatment temperature, heat treatment time, etc. of the reversible phase change layer 11 can be changed by adjusting parameters such as the spot size, energy density, pulse width, and wavelength of the incident laser, so that different regions of the reversible phase change layer 11 can be laser annealed using different heat treatment parameters, so that different regions generate stresses of different magnitudes, and the warpage of the wafer 100 can be adjusted more controllably.

[0059] In some embodiments of the present application, processing at least a portion of the reversible phase change layer 11 further includes: applying a current to at least one reversible phase change region 111 according to a warpage of the wafer 100 .

[0060] In some embodiments, current is applied to the reversible phase change zone 111, and the Joule heat generated by the current causes the reversible phase change zone 111 to undergo a reversible phase change between the crystalline phase and the amorphous phase. Compared with heat treatment, applying current can make the phase change of the reversible phase change zone 111 more controllable.

[0061] In some embodiments, an electrode interface may be provided in the reversible phase change region 111 , such as a welding pad, and a current is provided to the reversible phase change region 111 through a probe.

[0062] In some embodiments, an insulating layer may be provided between the reversible phase change layer 11 and the substrate 10 . Due to the presence of the insulating layer, a short circuit is formed between the reversible phase change layer 11 and the substrate 10 , thereby avoiding affecting the functional layer 12 of the wafer 100 .

[0063] When the reversible phase change region 111 is required to change from the crystalline phase to the amorphous phase, the pulse width and amplitude of the applied electric pulse signal are greater than the pulse width and amplitude of the applied electric pulse signal when the reversible phase change region 111 changes from the amorphous phase to the crystalline phase.

[0064] Furthermore, according to the warpage of the wafer 100 , the magnitude of the current applied to the reversible phase change zone 111 or the power-on time is adjusted so that different reversible phase change zones 111 have different phase change degrees, thereby being able to more accurately adjust the warpage of the wafer 100 .

[0065] In some embodiments of the present application, Figure 5 As shown, the reversible phase change layer 11 includes a reversible phase change region 111 and an insulating region 113 . Two adjacent reversible phase change regions 111 are isolated from each other by the insulating region 113 , so that the reversible phase change regions 111 do not interfere with each other.

[0066] In some embodiments, the reversible phase change region 111 may be in the shape of a long strip extending along the X or Y direction, or in the shape of a rectangle arranged in sequence along the X or Y direction, or in the shape of a fan.

[0067] The present application also provides a wafer 100. The wafer 100 may include a first surface and a second surface opposite to each other, wherein a reversible phase change layer 44 is formed on the second surface, and the reversible phase change layer 11 can produce a reversible phase change.

[0068] In some embodiments, at least part of the reversible phase change layer 11 is in the first phase, and at least part of the reversible phase change layer 11 is in the second phase. By adjusting the phase change of the reversible phase change layer 11, the wafer 100 has basically no warpage difference in different directions.

[0069] The semiconductor device provided in the present application can form a reversible phase change layer on the second surface of the wafer through the above-mentioned method of adjusting the warpage of the wafer. According to the warpage of the wafer, a partial area of ​​the reversible phase change layer is processed to control the phase change of the reversible phase change layer in the partial area to reduce the warpage of the wafer, making the wafer flatter, thereby reducing the error caused by the wafer warpage in subsequent processes, improving the intra-wafer uniformity of the wafer, and improving the subsequent yield of the wafer. At the same time, the characteristics of the reversible phase change layer can be used to program and erase the stress of the reversible phase change layer, so that the stress distribution of each area on the second surface of the wafer can be readjusted after the warpage of the wafer changes in the subsequent process, thereby further improving the flatness of the wafer.

[0070] In the above description, the technical details such as the patterning of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0071] The embodiments of the present application are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present application. The scope of the present application is limited by the attached claims and their equivalents. Without departing from the scope of the present application, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present application.

Claims

1. A method for adjusting the warpage of a wafer, characterized in that: The method comprises: Providing a wafer, the wafer comprising a first side and a second side opposite to each other; forming a reversible phase change layer on the second surface of the wafer, wherein the reversible phase change layer can undergo a reversible phase change; and According to the warpage of the wafer, at least a partial region of the reversible phase change layer is controlled to undergo phase change.

2. The method according to claim 1, characterized in that The material of the reversible phase change layer includes Ge-Sb-Te phase change material.

3. The method according to claim 1, characterized in that The at least partial area includes one or more reversible phase change zones, and the reversible phase change zones are capable of undergoing a reversible phase change. Controlling the phase change of at least a partial area of ​​the reversible phase change layer further includes: according to the warping of the wafer, heat treating at least one reversible phase change zone on the reversible phase change layer to cause the at least one reversible phase change zone to undergo a phase change.

4. The method according to claim 3, characterized in that The thermally treating the reversible phase change region further comprises: determining a processing configuration of the thermal treatment of the at least one reversible phase change region according to a warpage of the wafer.

5. The method according to claim 4, characterized in that The processing configuration includes: a first configuration, wherein the first configuration includes heat treating the at least one reversible phase change region at a temperature lower than 650 degrees Celsius for a heat treatment time greater than 5 minutes, and the at least one reversible phase change region transforms from an amorphous phase to a crystalline phase under the first configuration; or The second configuration includes heat treatment temperature of the at least one reversible phase change zone being higher than 650 degrees Celsius and heat treatment time being less than 2 minutes, and the at least one reversible phase change zone is transformed from a crystalline phase to an amorphous phase under the second configuration.

6. The method according to claim 5, characterized in that The heat treatment includes any one of laser annealing, ion beam annealing or electron beam annealing.

7. The method according to claim 3, characterized in that The controlling the phase change of at least a partial region of the reversible phase change layer further comprises: applying a current to the at least one reversible phase change region according to the warpage of the wafer.

8. The method according to claim 7, characterized in that The applying current to at least one of the reversible phase change zones further comprises: adjusting the magnitude of the current applied to the at least one reversible phase change zone and / or the power-on time according to the warpage of the wafer.

9. The method according to claim 8, characterized in that The applying of current to at least one of the reversible phase change zones further includes: applying an electric pulse signal to the at least one reversible phase change zone, and the pulse width and amplitude of the electric pulse signal applied when the at least one reversible phase change zone changes from the crystalline phase to the amorphous phase are greater than the pulse width and amplitude of the electric pulse signal applied when the at least one reversible phase change zone changes from the amorphous phase to the crystalline phase.

10. The method according to any one of claims 1 to 9, characterized in that: Two adjacent reversible phase change regions are isolated from each other by an insulating region.

11. A wafer, characterized in that: The wafer includes a first surface and a second surface opposite to the first surface, a reversible phase change layer is formed on the second surface, and the reversible phase change layer can undergo a reversible phase change.

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