Separation method of crystal grains and crystal grains

Abstract

The invention provides a crystal grain separation method and a crystal grain. The crystal grain separation method comprises the following steps: providing a wafer; the wafer is provided with a front surface and a back surface which are opposite to each other, and the front surface of the wafer is provided with a metal layer; the wafer is cut from the side where the back face of the wafer is located to form a plurality of grooves, and the plurality of grooves divide the wafer into a plurality of crystal grains to be separated; and carrying out film expansion treatment on the wafer by utilizing an expansion film attached to the front surface of the wafer so as to separate the plurality of crystal grains to be separated. The method not only has the performance advantages of the plasma cutting process, but also can expand the wafer with the metal layer in the cutting channel, and can effectively realize the separation of each crystal grain.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a crystal grain separation method and the crystal grains. Background Art

[0002] In the packaging process, the wafer needs to be cut into individual crystals. Among them, plasma cutting, as a high-level cutting process, can effectively cut silicon substrates, has excellent chipping performance, and is suitable for ultra-narrow cutting products, but the plasma process cannot cut metal. Therefore, for narrow cutting path wafers with metal in the cutting path, plasma cannot effectively cut the wafer into individual crystals. Summary of the invention

[0003] The present application provides a method for separating crystal grains and crystal grains, aiming to solve the problem that plasma cannot effectively cut a narrow cutting path wafer with metal in the cutting path into single crystal grains.

[0004] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a method for separating grains, the method comprising: providing a wafer; the wafer having a front side and a back side opposite to each other, and a metal layer is arranged on the front side of the wafer; cutting the wafer from the side where the back side of the wafer is located to form a plurality of grooves, and the plurality of grooves divide the wafer into a plurality of grains to be separated; and performing a film expansion treatment on the wafer using an expansion film attached to the front side of the wafer to separate the plurality of grains to be separated.

[0005] In one embodiment of the present application, the wafer further includes a substrate, and the metal layer is disposed on the substrate;

[0006] The step of cutting the wafer from the side where the back side of the wafer is located comprises:

[0007] The wafer is cut from a side of the substrate facing away from the metal layer and the cutting is stopped at least into the substrate.

[0008] In one embodiment of the present application, the cutting is performed from a side of the substrate facing away from the metal layer to a surface of a side of the metal layer facing the substrate.

[0009] In one embodiment of the present application, the wafer is subjected to a film expansion process from the side where the front side of the wafer is located by using the expansion film to separate the metal layer.

[0010] In one embodiment of the present application, the wafer is cut using a plasma cutting process to form the plurality of grooves.

[0011] In one embodiment of the present application, before the wafer is cut, the expansion film is attached to the front side of the wafer.

[0012] In one embodiment of the present application, the wafer is subjected to multiple film expansion processes using the expansion film.

[0013] In one embodiment of the present application, when the wafer is subjected to film expansion processing, the wafer is fixed to a fixing component of the separation platform through the expansion film; the film expansion fixture of the separation platform is configured to lift the expansion film along a first direction;

[0014] In each film expansion process, the lifting height of the film expansion fixture along the first direction is positively correlated with the number of times of the film expansion process.

[0015] In one embodiment of the present application, the step of performing multiple film expansion processes on the wafer using the expansion film includes:

[0016] Fixing the wafer on the separation platform through the expansion film;

[0017] driving a first film expanding plate of a film expanding fixture of the separation platform to lift up the expanded film along a first direction, so that the expanded film undergoes a first film expanding process;

[0018] The at least one second film expanding plate of the film expanding fixture is driven to further lift the expanded film relative to the first film expanding plate along the first direction, so that the expanded film undergoes at least one second film expanding process.

[0019] In one embodiment of the present application, the step of driving at least one second film expanding plate of the film expanding fixture to further lift the expanded film along the first direction includes:

[0020] According to the order in which the cross-sectional area of ​​at least one second film expanding plate of the film expanding fixture gradually decreases, the at least one second film expanding plate is driven in sequence to further lift the expanded film relative to the first film expanding plate along the first direction; wherein, the at least one second film expanding plate is coaxially arranged with the first film expanding plate; and the cross-sectional area of ​​each of the second film expanding plates is smaller than the cross-sectional area of ​​the first film expanding plate.

[0021] In order to solve the above technical problem, another technical solution adopted in the present application is: to provide a crystal grain separated by the above-mentioned crystal grain separation method.

[0022] The beneficial effects of the embodiments of the present application are different from those of the prior art: the grain separation method provided in the present embodiment is to cut the wafer from the side where the back of the wafer is located to form a plurality of grooves, and the plurality of grooves divide the wafer into a plurality of grains to be separated; and then the wafer is subjected to a film expansion treatment using an expansion film attached to the front of the wafer. In this way, the separation method has the performance advantages of the plasma cutting process; and even if a metal layer is provided on the front of the wafer and the cutting process cannot cut the metal, the metal layer can be further expanded by film expansion treatment after cutting, thereby dividing the wafer into a plurality of single grains. At the same time, separation of the metal layer by film expansion treatment will not generate high temperature, thereby effectively avoiding the problem that the substrate and / or metal layer cracks due to high temperature, thereby causing the entire product to fail. In addition, the cost of the film expansion process is low, and it is suitable for mass production of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0024] Figure 1 A flow chart of a method for separating grains provided in one embodiment of the present application;

[0025] Figure 2 A schematic diagram of the structure of a wafer provided in one embodiment of the present application;

[0026] Figure 3 for Figure 1 Schematic diagram of the process of step S2;

[0027] Figure 4 For the Sutra Figure 1 Schematic diagram of the product structure after step S2 processing;

[0028] Figure 5 For Figure 4 Schematic diagram of the process of film expansion treatment of the structure shown;

[0029] Figure 6 For the Sutra Figure 1 Schematic diagram of the product structure after step S3 processing;

[0030] Figure 7 A schematic diagram of the structure of a film expansion fixture provided in one embodiment of the present application;

[0031] Figure 8 A schematic diagram of a process of performing a second film expansion process on a wafer using a second film expansion plate;

[0032] Fig. 9 A schematic diagram of the structure of a second film expansion disk provided in one embodiment of the present application;

[0033] Fig.10 A schematic structural diagram of a first film expansion disk provided in another embodiment of the present application;

[0034] Fig.11 A schematic diagram of the structure of a film expansion fixture provided in another embodiment of the present application.

[0035] Description of Reference Numerals

[0036] 1 wafer; 10 crystal grain; 11 substrate; 12 metal layer; 121 dielectric layer; 122 metal structure; 13 groove; 2 expansion film; 3 expansion jig; 31 first expansion plate; 311 through hole; 32 second expansion plate; 32a expansion block; Y first direction; A front side; B back side. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] The terms "first", "second", "third" in this application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", "third" can expressly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the embodiments of this application, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the steps or units listed, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0039] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] The present application is described in detail below with reference to the accompanying drawings and embodiments.

[0041] See also Figure 1 , Figure 1 A flow chart of a method for separating grains provided in one embodiment of the present application; in this embodiment, a method for separating grains is provided, the method comprising:

[0042] Step S1: providing a wafer; the wafer has a front side and a back side facing each other, and a metal layer is disposed on the front side of the wafer.

[0043] See also Figure 2 , Figure 2 A schematic diagram of the structure of a wafer 1 provided in an embodiment of the present application. The wafer 1 has a dicing path. The wafer 1 may include a substrate 11 and a metal layer 12 disposed on the substrate 11. The substrate 11 may be any suitable base material known in the art, for example, at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (SiC), carbon germanium silicon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI) and germanium on insulator (GeOI).

[0044] It should be noted that the "M component" involved in this application is arranged on the "N component", which means that the M component is arranged on the side where the front of the N component is located, and it is not required that the M component is directly attached to the N component. Other film structures may be arranged between the M component and the N component. For example, the metal layer 12 is arranged on the substrate 11, which means that the metal layer 12 is located on the side where the front of the substrate 11 is located, and the metal layer 12 may be directly attached to the front of the substrate 11; or there may be other film structures between the metal layer 12 and the substrate 11, and this application does not limit this.

[0045] The metal layer 12 includes a dielectric layer 121 and a metal structure 122 disposed in the dielectric layer 121. The metal structure 122 may be a structure known to those skilled in the art for electrical connection, such as a hybrid bonding structure, a metal bump, a through silicon via structure, a redistribution layer, and other metal structure layers. The side of the metal structure 122 facing away from the substrate 11 may be exposed from the dielectric layer 121, so that the metal structure 122 may be electrically connected to other devices in subsequent processes.

[0046] The surface of the metal layer 12 facing away from the substrate 11 is the front side A of the wafer 1 , and the surface of the substrate 11 facing away from the metal layer 12 is the back side B of the wafer 1 .

[0047] Step S2: cutting the wafer from the side where the back side of the wafer is located to form a plurality of grooves, and the plurality of grooves divide the wafer into a plurality of crystal grains to be separated.

[0048] In the specific implementation process, see Figure 3 and Figure 4 , Figure 3 for Figure 1 Schematic diagram of the process of step S2; Figure 4 For the Sutra Figure 1 Schematic diagram of the product structure after step S2 in FIG. 1 ; the expansion film 2 can be attached to the front side A of the wafer 1. Then the wafer 1 is cut from the side where the back side B of the wafer 1 is located; the product structure after cutting can be seen in FIG. Figure 4 .

[0049] Among them, the expansion film 2 can be pressed on the front side A of the wafer 1 by vacuum lamination. The cutting path of the wafer 1 is cut by a plasma cutting process to form a plurality of grooves 13. Among them, the wafer 1 is cut by a plasma cutting process, and non-rectangular grains 10, such as hexagonal grains 10, can be operated, that is, in some embodiments, the plasma cutting process does not have high requirements on the shape of the cutting path, while the ordinary cutting method can usually only cut a whole wafer 1 in a straight line. In addition, compared with knife cutting, plasma cutting applies less mechanical force to the wafer 1, and the chipping of the grain 10 is smaller. The chipping refers to the notch produced by the grain 10 along the cutting path during the cutting process, that is, the appearance damage of the grain 10. In addition, compared with laser cutting, plasma cutting applies less heat to the wafer 1. Of course, in some embodiments, laser cutting can also be used to implement the above-mentioned cutting steps.

[0050] In one embodiment, step S2 specifically cuts the wafer 1 from the side of the substrate 11 away from the metal layer 12 and at least cuts into the substrate 11 . That is, the groove 13 extends from the surface of the substrate 11 away from the metal layer 12 at least into the substrate 11 .

[0051] Specific, combined Figure 4 , step S2 can be cut from the side of the substrate 11 away from the metal layer 12 to the side of the metal layer 12 facing the substrate 11. That is, the groove 13 extends from the side of the substrate 11 away from the metal layer 12 to the side of the metal layer 12 facing the substrate 11. In this way, the wafer 1 can be separated to the greatest extent through the cutting process to reduce the risk of chipping of the wafer 1.

[0052] Among them, when other processes such as laser cutting and knife cutting are used to cut the wafer 1, over-engraving may occur in some implementation processes, that is, the cutting process cannot be accurately terminated on the side surface of the metal layer 12 facing the substrate 11, and the groove 13 may further extend into the metal layer 12.

[0053] The diameter of the expansion film 2 is larger than the diameter of the wafer 1, so as to ensure that the subsequent wafer 1 can be fixed on the separation platform through the expansion film 2, and to ensure that the expansion film 2 has sufficient strength for subsequent expansion. The expansion film 2 is made of a material with good ductility. For example, the expansion film 2 can be made of polyethylene (polyethylene, poly) material.

[0054] Among them, although the plasma cutting process is used to cut the wafer 1, it has many benefits as mentioned above, but because plasma cannot react with heavy metal materials, the plasma cutting process cannot cut the metal layer 12. Therefore, other processes are needed to further separate the metal layer 12. The inventors of this application have found that if laser cutting is used to cut the metal layer 12, since the laser process will generate high temperature, and the thermal expansion coefficients between the substrate 11 and the metal layer 12 are different, the laser process will cause the substrate 11 and the metal layer 12 to crack, and then cause the entire product to fail. If other processes that do not generate high temperatures, such as etching processes, are used, although the metal layer 12 can be separated, the cost of the etching process is relatively high and is not suitable for mass production of products. For this reason, the inventors of this application choose to separate the metal layer 12 by film expansion processing, as described below.

[0055] Step S3: performing film expansion processing on the wafer using the expansion film attached to the front side of the wafer to separate a plurality of dies to be separated.

[0056] See also Figure 5 and Figure 6 , Figure 5 For Figure 4 Schematic diagram of the process of film expansion treatment of the structure shown; Figure 6 For the Sutra Figure 1 Schematic diagram of the product structure after step S3 is processed. In the specific implementation process, step S3 specifically includes:

[0057] Step S31: fix the wafer 1 on the separation platform through the expansion film 2.

[0058] The separation platform includes a carrier (not shown) and a fixing assembly (not shown) disposed on the carrier, a film expansion fixture 3 and a driving assembly (not shown). The fixing assembly is configured to fix the expansion film 2; the expansion film 2 has a first side and a second side opposite to each other, a wafer 1 is disposed on the first side of the expansion film 2, and the second side of the expansion film 2 is configured to face the separation platform so as to perform film expansion processing on the wafer 1. The wafer 1 has a plurality of grains 10 to be separated formed after cutting.

[0059] In some embodiments, the wafer 1 has a plurality of dies 10 to be separated after being cut, and the "cutting" involved includes complete cutting and incomplete cutting. Complete cutting means that after the wafer 1 is cut, the plurality of dies 10 are completely cut; incomplete cutting means that after the wafer 1 is cut, the plurality of dies 10 are not completely cut.

[0060] The fixing assembly may include a clamping member, which is fixedly connected to the carrier platform and is configured to clamp and fix the expansion membrane 2 from the circumferential edge of the expansion membrane 2. Specifically, there may be multiple clamping members, which are arranged at intervals. Alternatively, the clamping member may be in a closed loop shape to clamp and fix the expansion membrane 2 along the circumference of the expansion membrane 2. Of course, the clamping member may also be in a non-closed loop shape.

[0061] The film expansion jig 3 is configured to separate the crystal grain 10 in the wafer 1 fixed on the separation platform through the expansion film 2. The driving component is connected to the film expansion jig 3 and is configured to drive the film expansion jig 3 to move up and down along the first direction Y to lift the expansion film 2 fixed on the separation platform so that the expansion film 2 is expanded, thereby separating the crystal grain 10. The film expansion jig 3 may include a film expansion disk. The driving component may include at least one driving member, which may be a motor.

[0062] In the specific implementation process, the front side A of the wafer 1 is directed toward the film expansion jig 3 and fixed to the fixed component through the expansion film 2. Then, the expansion film 2 attached to the front side A of the wafer 1 is used to expand the wafer 1 from the side where the front side A of the wafer 1 is located, so as to separate the metal layer 12. For details, see step S32.

[0063] Step S32 : driving the film expansion jig 3 to rise to lift up the expansion film 2 .

[0064] After the wafer 1 is fixed on the separation platform, the film expansion jig 3 is driven to rise along the first direction Y by the driving component, so that the middle area of ​​the expansion film 2 is lifted relative to the film expansion jig 3. Since the circumferential edge of the expansion film 2 is fixed on the fixing component of the separation platform, and the wafer 1 is attached to the expansion film 2; therefore, after the middle area of ​​the expansion film 2 is lifted, the wafer 1 is also lifted, so that the metal layer 12 on the wafer 1 is effectively expanded, so as to separate the wafer 1 into multiple grains 10. The product structure after the film expansion process can be seen in Figure 6 .

[0065] In some embodiments, if one film expansion treatment cannot completely expand the metal layer 12, or the grains 10 at the center of the wafer 1 have not been completely separated, the wafer 1 can be subjected to multiple film expansion treatments using the expansion film 2 to ensure that the metal layer 12 of the wafer 1 can be completely expanded, thereby effectively achieving the separation of the grains 10 to be separated after cutting.

[0066] In each film expansion process, the lifting height of the film expansion jig 3 along the first direction Y is positively correlated with the number of film expansion processes. That is, each additional film expansion process increases the lifting height of the film expansion jig 3 along the first direction Y. In particular, by gradually increasing the lifting height of the film expansion jig 3, the metal layer 12 at the corresponding position can be more effectively separated, so as to fully expand the metal layer 12 that has not been separated after cutting as much as possible, thereby achieving complete separation of the grains 10 to be separated.

[0067] In this embodiment, see Figure 7 , Figure 7 This is a schematic structural diagram of a film expansion jig 3 provided in one embodiment of the present application; the film expansion jig 3 may include a first film expansion plate 31 and at least one second film expansion plate 32 .

[0068] The first film expanding plate 31 is configured to be movable along the first direction Y to lift up the expanded film 2 fixed on the separation platform so that the expanded film 2 undergoes a first film expanding treatment.

[0069] Among them, after the expansion film 2 is fixed on the separation platform, the central axis of the wafer 1 coincides or almost coincides with the central axis O of the first expansion film disk 31. In this way, the expansion film fixture 3 can be used to separate the grains 10 in more areas of the wafer 1, thereby improving the uniformity of the force and improving the separation effect of the expansion film fixture 3 on the wafer 1.

[0070] In a specific embodiment, the driving component drives the first film expansion plate 31 to move and rise along the first direction Y, so that the expansion film 2 is lifted relative to the supporting platform by the first film expansion plate 31. Since the circumferential edge of the expansion film 2 is fixed to the fixing component of the separation platform, and the wafer 1 is attached to the expansion film 2; therefore, after the middle area of ​​the expansion film 2 is lifted, the wafer 1 is also lifted, so that the grains 10 to be separated on the wafer 1 are separated.

[0071] The shape of the first film expansion plate 31 matches the shape of the wafer 1, and the maximum area of ​​the first film expansion plate 31 is equal to or nearly equal to the area of ​​the wafer 1, so that after the wafer 1 and the first film expansion plate 31 are coaxially arranged, it can be ensured that the first film expansion plate 31 can perform film expansion processing on the entire wafer 1. In some embodiments, the maximum area of ​​the first film expansion plate 31 is smaller than the area of ​​the wafer 1.

[0072] In one embodiment, in combination Figure 7 The first film expansion disk 31 may be in a hollow ring shape, that is, the first film expansion disk 31 has a hollow area. At least one second film expansion disk 32 is disposed in the hollow area of ​​the first film expansion disk 31 .

[0073] At least one second film expansion plate 32 is respectively configured to be electrically connected to the driving component, and the driving component can drive each second film expansion plate 32 to rise relative to the first film expansion plate 31 along the first direction Y to further lift the expansion film 2, so that the expansion film 2 undergoes at least one second film expansion process until the metal layer 12 of the wafer 1 on the expansion film 2 is completely separated. Among them, each second film expansion plate 32 can be configured to rise or fall independently along the first direction Y.

[0074] Combination Figure 7 The second film expanding disk 32 is arranged along the direction close to the central axis O of the first film expanding disk 31, and all the second film expanding disks 32 of the film expanding fixture 3 are sequentially sleeved in the hollow area of ​​the first film expanding disk 31, that is, all the second film expanding disks 32 are sleeved in a ring, and the first film expanding disk 31 is sleeved on the outside of all the second film expanding disks 32.

[0075] The two adjacent film expansion plates may be in contact with each other and arranged adjacent to each other, or there may be a certain gap between the two adjacent film expansion plates, so that the friction force generated by the contact between the two film expansion plates can be prevented from hindering the lifting process of the film expansion plates.

[0076] See also Figure 8 , Figure 8The schematic diagram is a process diagram of performing a second film expansion treatment on a wafer using a second film expansion plate; after the first film expansion treatment, the first film expansion plate 31 can be kept in a raised state; then the second film expansion plate 32 is configured to be further raised relative to the first film expansion plate 31 along the first direction Y. It can be understood that during the entire separation process, the total lifting height of the second film expansion plate 32 relative to the carrier along the first direction Y is greater than the total lifting height of the first film expansion plate 31 relative to the carrier along the first direction Y. In this way, compared to only setting up the first film expansion plate 31, by adding at least one second film expansion plate 32, the height of the expanded film 2 being lifted along the first direction Y and the number of times the film expansion treatment is performed on the wafer 1 can be increased, so as to more effectively expand the metal layer 12.

[0077] In one embodiment, the cross-sectional area of ​​each second film expansion disk 32 is smaller than the cross-sectional area of ​​the first film expansion disk 31. In this way, during the second film expansion process, the second film expansion disk 32 can perform film expansion processing on a local area of ​​the wafer 1 through the expansion film 2, thereby more effectively separating the die 10. It should be noted that the cross-sectional area of ​​the film expansion disk involved in this patent refers to the area of ​​the entire area surrounded by the outer edge of the film expansion disk.

[0078] In one embodiment, see Figure 7 , multiple second film expansion plates 32 are independently arranged, and each second film expansion plate 32 is configured to rise or fall independently. Specifically, the number of second film expansion plates 32 can be one or more; the cross-sectional areas of the multiple second film expansion plates 32 are different, and all the second film expansion plates 32 are coaxially arranged with the first film expansion plate 31. It can be understood that along the direction close to the central axis O of the first film expansion plate 31, the cross-sectional areas of the multiple second film expansion plates 32 gradually decrease. In this way, the second film expansion plate 32 with gradually decreasing cross-sectional areas can be used to perform a second film expansion treatment on each area of ​​the wafer 1 from the edge to the center in sequence using the expansion film 2 to expand the metal layer 12 between each grain 10 in a small area, thereby further improving the separation effect of the grains 10.

[0079] In some embodiments, when the film expansion jig 3 includes two second film expansion disks 32, along the direction close to the central axis O of the first film expansion disk 31, the ratio of the cross-sectional area of ​​the two second film expansion disks 32 to the cross-sectional area of ​​the first film expansion disk 31 can be two-thirds and one-third, or other suitable values. When the film expansion jig 3 includes three second film expansion disks 32, along the direction close to the central axis O of the first film expansion disk 31, the ratio of the cross-sectional area of ​​the three second film expansion disks 32 to the cross-sectional area of ​​the first film expansion disk 31 can be three-quarters, two-quarters and one-quarter, or other suitable values, and so on.

[0080] Among them, combined Figure 5 and Figure 7In the process of separating the dies 10, the total lifting height of each second film expansion plate 32 relative to the carrier along the first direction Y is negatively correlated with the cross-sectional area of ​​the second film expansion plate 32. That is, the closer the second film expansion plate 32 is to the central axis O of the first film expansion plate 31, the greater the total lifting height of the second film expansion plate 32 relative to the carrier along the first direction Y. In this way, by gradually increasing the lifting height of the second film expansion plate 32, the dies 10 at the corresponding positions can be separated more effectively, so as to separate the dies 10 in the central area of ​​the wafer 1 as much as possible.

[0081] It should be noted that the total lifting height of the second film expansion plate 32 relative to the supporting platform along the first direction Y involved in the present application may be less than or equal to the maximum height that the second film expansion plate 32 can be lifted along the first direction Y. The maximum height that the second film expansion plate 32 can be lifted along the first direction Y refers to the maximum height that the driving member can drive the second film expansion plate 32 to reach along the first direction Y relative to the supporting platform.

[0082] In a specific embodiment, in combination Figures 5 to 8 The driving assembly can sequentially drive the plurality of second film expansion plates 32 to rise relative to the first film expansion plate 31 in the order in which the cross-sectional areas of the second film expansion plates 32 gradually decrease. The driving assembly can include a plurality of driving members, one driving member correspondingly connected to a first film expansion plate 31 or a second film expansion plate 32, so as to drive the first film expansion plate 31 or the second film expansion plate 32 to independently move up and down along the first direction Y.

[0083] In a specific embodiment, the number of the second film expansion disk 32 is specifically two, namely a large film expansion disk and a small film expansion disk, the large film expansion disk and the small film expansion disk have different cross-sectional areas, and the large film expansion disk is annularly sleeved on the outside of the small film expansion disk, and the first film expansion disk 31 is annularly sleeved on the outside of the large film expansion disk. In the specific working process, the first film expansion disk 31, the large film expansion disk and the small film expansion disk can be driven to rise simultaneously relative to the bearing platform along the first direction Y. Then the large film expansion disk and the small film expansion disk are driven to further lift up relative to the first film expansion disk 31; and then the small film expansion disk is driven to further lift up relative to the large film expansion disk. It can be understood that the total lifting height of the large film expansion disk relative to the bearing platform is greater than the total lifting height of the first film expansion disk 31 relative to the bearing platform; the total lifting height of the small film expansion disk relative to the bearing platform is greater than the total lifting height of the large film expansion disk relative to the bearing platform.

[0084] In some embodiments, a second film expansion disk 32 closest to the central axis O of the first film expansion disk 31 is a solid disk; in this way, the second film expansion disk 32 can be used to perform film expansion processing on each position in the central area of ​​the wafer 1 to increase the probability that the grains 10 in the central area of ​​the wafer 1 can be separated.

[0085] The cross-sectional area of ​​the second film expansion disk 32 closest to the central axis O of the first film expansion disk 31 is not greater than 9 mm.2 ; For example, the cross-sectional area of ​​the solid disk may be 9mm 2 , 8mm 2 , 7mm 2 、6mm 2 , 5mm 2 , 4mm 2 , 3mm 2 , 2mm 2 , 1mm 2 In this way, the second film expansion disk 32 can be used to expand the cross-sectional area of ​​less than 9mm 2 The crystal grains 10 are separated, so that the application range of the film expansion jig 3 is wider.

[0086] The remaining second film expansion disks 32 are all hollow ring-shaped; specifically, they can be hollow closed ring-shaped. When the film expansion fixture 3 is idle, that is, not lifted up, multiple second film expansion disks 32 in the shape of hollow closed rings are sequentially sleeved on the circumferential outer side of the second film expansion disk 32 of the solid disk.

[0087] Specifically, the first film expansion disk 31 and the second film expansion disk 32 in the hollow ring shape can both be hollow discs. The first film expansion disk 31 and all the second film expansion disks 32 can form a solid disc. The thickness and material of the second film expansion disk 32 can be the same or similar to the material of the first film expansion disk 31. Specifically, the thickness of the second film expansion disk 32 can be the same as the thickness of the first film expansion disk 31. In this way, in the process of manufacturing the film expansion jig 3, the first film expansion disk 31 and at least one second film expansion disk 32 can be formed separately on the same film expansion disk through a cutting process or other separation processes, which is simple to manufacture and low in cost.

[0088] In this embodiment, the step of performing multiple film expansion processes on the wafer 1 using the expansion film 2 includes:

[0089] Step A: Fix the wafer 1 on the separation platform through the expansion film 2.

[0090] The specific implementation process of step A is the same or similar to the above step S31.

[0091] Step B: driving the first film expanding plate 31 of the film expanding fixture 3 of the separation platform to lift the expanded film 2 along the first direction Y, so that the expanded film 2 undergoes a first film expanding treatment to separate the grains 10 on the expanded film 2; wherein the first direction Y is the direction from the second side of the expanded film 2 to the first side, and the second side is relative to the first side.

[0092] In the specific implementation process, the first film expansion plate 31 is driven by the driving component to rise relative to the supporting platform along the first direction Y, so as to lift the expansion film 2 along the first direction Y, thereby separating the metal layer 12 of the wafer 1 disposed on the expansion film 2 .

[0093] In one embodiment, while driving the first film expansion plate 31 to rise, all the second film expansion plates 32 on the film expansion fixture 3 can be synchronously driven to rise relative to the carrier platform along the first direction Y, so as to use at least one second film expansion plate 32 to synchronously lift the expansion film 2 and perform the first film expansion process on the wafer 1, so that the film expansion process can separate more grains 10 on the wafer 1 and improve the film expansion efficiency. The lifting heights of the first film expansion plate 31 and all the second film expansion plates 32 are the same.

[0094] Of course, in another embodiment, step B may also only drive the first film expanding plate 31 to rise along the first direction Y relative to the supporting platform, and all the second film expanding plates 32 remain stationary along the first direction Y relative to the supporting platform.

[0095] Step C: drive at least one second film expanding plate 32 of the film expanding fixture 3 to further lift the expanded film 2 along the first direction Y relative to the first film expanding plate 31, so that the expanded film 2 undergoes at least one second film expanding treatment; wherein the second film expanding plate 32 can be lifted along the first direction Y relative to the first film expanding plate 31.

[0096] In the specific implementation process, combined with Figure 8 , step C specifically includes:

[0097] Step C1: in the order in which the cross-sectional area of ​​at least one second film expanding plate 32 of the film expanding fixture 3 gradually decreases, at least one second film expanding plate 32 is driven in sequence to further lift the expanded film 2 along the first direction Y relative to the first film expanding plate 31 .

[0098] The second film expansion plate 32 further lifts the expansion film 2 relative to the first film expansion plate 31, which means that during the execution of step C, the first film expansion plate 31 remains in a raised state, and the second film expansion plate 32 is further raised relative to the first film expansion plate 31 to further lift the expansion film 2. It can be understood that the lifting height of the second film expansion plate 32 relative to the fixed component is greater than the lifting height of the first film expansion plate 31 relative to the fixed component.

[0099] In some embodiments, the total lifting height of the second film expansion plate 32 relative to the carrier along the first direction Y is negatively correlated with the cross-sectional area of ​​the second film expansion plate 32. In this way, during the execution of step C1, by gradually increasing the lifting height of the second film expansion plate 32, the dies 10 at the corresponding positions can be more effectively separated, so as to separate the dies 10 in the central area of ​​the wafer 1 as much as possible. It should be noted that the lifting height or lifting height of the film expansion plate involved in this application is relative to the height of the fixed component.

[0100] Of course, in the specific implementation process, if there are still unseparated grains 10 on the wafer 1, the wafer 1 can continue to be subjected to the second film expansion treatment for the third, fourth or even more times until the grains 10 on the wafer 1 are completely separated.

[0101] In this embodiment, the second film expansion plate 32 with a gradually decreasing cross-sectional area can be used to sequentially perform a second film expansion process on each region from the edge to the center of the wafer 1 using the expansion film 2, so as to gradually separate the grains 10 in the small area, thereby further improving the separation effect of the grains 10. At the same time, by gradually increasing the jacking height of the second film expansion plate 32, the grains 10 at the corresponding positions can be separated more effectively, so as to separate the grains 10 in the central area of ​​the wafer 1 as much as possible.

[0102] In one embodiment, see Fig. 9 , Fig. 9 A schematic structural diagram of a second film expansion disk provided in an embodiment of the present application; each second film expansion disk 32 includes a plurality of film expansion blocks 32a along its circumferential direction, the plurality of film expansion blocks 32a are independently arranged, and each film expansion block 32a is configured to be independently raised or lowered.

[0103] The sizes of the multiple film expansion blocks 32a can be the same or different, or some can be the same and some can be different. In some embodiments, one film expansion block 32a can be connected to a corresponding driving member to independently drive the film expansion block 32a to rise or fall relative to the supporting platform.

[0104] It can be understood that when the second film expanding disk 32 is a solid disk, each film expanding block 32 a can be in a fan-shaped structure and contact at the center of the corresponding second film expanding disk 32 .

[0105] Among them, two adjacent film expansion blocks 32a can contact each other; or there can be a certain gap between two adjacent film expansion blocks 32a, so that the friction force generated by the contact between the two film expansion blocks 32a can be prevented from hindering the rising or lowering process of the film expansion block 32a. The length of the film expansion block 32a along the circumferential direction of the second film expansion disk 32 can be set according to actual conditions, and this application does not limit this.

[0106] In this embodiment, after step C, if the die 10 in the predetermined position area has not been completely separated, step D may be continued.

[0107] Step D: driving the film expanding block 32a at the preset position to further lift the expanded film 2 along the first direction Y relative to the second film expanding plate 32 where the film expanding block 32a is located, so that the expanded film 2 undergoes at least one third film expanding process.

[0108] In the specific implementation process, if the metal layer 12 in the preset position area has not been completely separated, the above solution can be used to further separate the metal layer 12 in a smaller area using the expansion block 32a to separate the multiple grains 10 at the corresponding positions.

[0109] For ease of understanding, the second film expansion disk 32 of the outermost circle is taken as an example to explain "the film expansion block 32a further lifts the expansion film 2 relative to the second film expansion disk 32 where the film expansion block 32a is located along the first direction Y". The second film expansion disk 32 of the outermost circle includes multiple film expansion blocks 32a. If the part of the crystal grains 10 corresponding to the second film expansion disk 32 of the outermost circle has not been completely separated, the part of the film expansion blocks 32a of the second film expansion disk 32 of the outermost circle is driven to further lift the expansion film 2 relative to the plane where the second film expansion disk 32 of the outermost circle is located, so as to perform a third film expansion process on the crystal grains 10 at the corresponding positions.

[0110] In the specific implementation process, each film expansion block 32a can be driven to rise along the first direction Y relative to the second film expansion plate 32 where the film expansion block 32a is located, so as to separate the metal layer 12 of a certain area of ​​the wafer 1. When the metal layers 12 of multiple different areas of the wafer 1 are not completely separated, the film expansion blocks 32a at the corresponding positions can be driven to rise at the same time to perform the third film expansion process respectively. The film expansion blocks 32a at each position can also be driven to rise in sequence, so as to perform the third film expansion process on each position in sequence.

[0111] Of course, in the process of driving the second film expansion plate 32 to lift the expansion film 2 along the first direction Y relative to the first film expansion plate 31 to perform the second film expansion treatment, some film expansion blocks 32a in the second film expansion plate 32 can also be driven to lift the expansion film 2 along the first direction Y relative to the first film expansion plate 31 to save energy consumption of the driving component.

[0112] In another embodiment, after step C, if the die 10 in the preset position area has not been completely separated, the method further includes:

[0113] Step D′: unlock the wafer 1 from the separation platform and re-fix it on another separation platform via the expansion film 2 .

[0114] Among them, another separation platform can be provided by the following embodiments including Fig.11 The separation platform of the film expansion fixture shown. When the wafer 1 is fixed to another separation platform through the expansion film 2, the unseparated grains 10 on the wafer 1 are at least corresponding to one third film expansion plate. The third film expansion plate can be Fig.11 The second film expansion plate 32 or similar in the film expansion fixture shown Fig.11 The second film expanding plate 32 in the film expanding fixture is shown.

[0115] Step E': driving at least one third film expanding plate of the film expanding fixture of another separation platform to further lift the expanded film 2 relative to the first film expanding plate 31 along the first direction Y, so that the expanded film 2 undergoes at least one third film expanding process.

[0116] Among them, at least one third film expansion disk is adjacent or spaced apart, and the central axes of every two third film expansion disks are spaced apart; that is, any two third film expansion disks are not coaxially arranged. The cross-sectional area of ​​each third film expansion disk is smaller than the cross-sectional area of ​​any second film expansion disk 32; in this way, the third film expansion disk can be used to further separate the metal layer 12 in a smaller area, so as to expand the grains 10 in the corresponding area, and realize the complete separation of each grain 10.

[0117] In the specific implementation process, each third film expansion plate can be driven to rise relative to the carrier platform along the first direction Y to separate the metal layer 12 of a certain area of ​​the wafer 1. When the metal layers 12 of multiple different areas of the wafer 1 are not completely separated, the third film expansion plates at the corresponding positions can be driven to rise at the same time to perform the third film expansion process respectively. The third film expansion plates at each position can also be driven to rise in sequence to perform the third film expansion process on each position in sequence.

[0118] In some embodiments, during the execution of step E', the orthographic projection of at least one third film expansion disk on wafer 1 is at least located at other positions of wafer 1 different from the central position of wafer 1; to ensure that the metal layer 12 located at other positions of wafer 1 different from the central position of wafer 1 can be subjected to the third film expansion treatment by the third film expansion disk to further separate these metal layers 12.

[0119] In yet another embodiment, see Fig.10 and Fig.11 , Fig.10 A schematic structural diagram of a first film expansion disk provided in another embodiment of the present application; Fig.11 A schematic diagram of the structure of a film expansion jig provided in another embodiment of the present application. Another film expansion jig 3 is provided, which is similar to the above Figure 7 The film expansion jig provided in the corresponding embodiment is different in that the first film expansion plate 31 has at least one through hole 311. Each through hole 311 penetrates the first side surface and the second side surface of the first film expansion plate 31. There are multiple second film expansion plates 32, and the multiple second film expansion plates 32 are adjacently or spaced apart in these through holes 311.

[0120] In one embodiment, the first film expansion disk 31 has a through hole 311; a plurality of second film expansion disks 32 are disposed in the through hole 311. Two adjacent second film expansion disks 32 may contact each other. Alternatively, there may be a certain gap between two adjacent second film expansion disks 32, that is, two adjacent second film expansion disks 32 are completely spaced apart.

[0121] In another embodiment, the first film expansion disk 31 has a plurality of through holes 311 , and the plurality of through holes 311 are arranged at intervals; and a second film expansion disk 32 is arranged in one through hole 311 .

[0122] In this embodiment, the cross-sectional areas of the plurality of second film expansion disks 32 may be the same or different, or some of the second film expansion disks 32 may have the same cross-sectional areas, while some of the second film expansion disks 32 may have different cross-sectional areas.

[0123] In this embodiment, the cross-sectional area of ​​each second film expansion disk 32 is not greater than 9 mm2; for example, the cross-sectional area of ​​the second film expansion disk 32 may be 9 mm2. 2 , 8mm 2 , 7mm 2 、6mm 2 , 5mm 2 , 4mm 2 , 3mm 2 , 2mm 2 , 1mm 2 In this way, the second film expansion disks 32 can be used to expand the cross-sectional area of ​​the film to less than 9mm. 2 The crystal grains 10 are separated, so that the application range of the film expansion fixture is wider.

[0124] In some embodiments, Fig.11 As shown, the ratio of the sum of the cross-sectional areas of all the second film expansion plates 32 to the cross-sectional area of ​​the first film expansion plate 31 is 0.9-1; for example, the ratio may be 0.9, 0.92, 0.95, 0.97 or 1, etc. In this way, after the first film expansion process, no matter which area of ​​the metal layer 12 of the wafer 1 is not separated, the film expansion process can be continued by the second film expansion plate 32 of the film expansion fixture to further separate the metal layer 12.

[0125] In this embodiment, after the wafer 1 undergoes a first film expansion treatment through the first film expansion plate 31, if there is still part of the metal layer 12 at a local position of the wafer 1 that has not been separated, the second film expansion plate 32 at the corresponding position can be driven to rise independently to lift up the expansion film 2, thereby performing a second film expansion treatment on the metal layer 12 at that position to separate the metal layer 12 at that position.

[0126] That is, the plurality of second film expansion plates 32 are configured to be able to be raised or lowered individually, so as to perform the second film expansion process on the unseparated metal layer 12 in certain specific areas of the wafer 1, so as to separate the metal layer 12 at the corresponding position. Of course, the plurality of second film expansion plates 32 can also be configured to be driven simultaneously, so as to perform the second film expansion process on the metal layer 12 in most areas of the wafer 1 at the same time through these second film expansion plates 32, so as to completely separate the grains 10 at the corresponding positions.

[0127] The lifting heights of the plurality of second film expansion plates 32 may be the same or different, and may be specifically designed according to actual needs.

[0128] With the above Figure 7 Compared with the film expansion jig 3 provided in the corresponding embodiment, the film expansion jig 3 provided in this embodiment can not only perform the second film expansion treatment on the metal layer 12 in most areas of the wafer 1, but also can perform the film expansion treatment on the metal layer 12 in a local area of ​​the wafer 1 separately, so as to further improve the separation effect of the grains 10.

[0129] In yet another embodiment, the separation method of the grains may be used alone to include Fig.11 The corresponding embodiment provides a separation platform for the expansion jig. Fig.11 The relevant introduction of the film expansion jig provided in the corresponding embodiment can be found above. In this embodiment, the method for separating the grains is different from the method for separating the grains provided in the above embodiment in that: Step C specifically includes:

[0130] Step C′: driving at least one second film expanding plate 32 of the film expanding fixture to simultaneously or sequentially lift up relative to the first film expanding plate 31 along the first direction Y, so that the expanded film 2 undergoes at least one second film expanding process.

[0131] Among them, combined Fig.11 There are multiple second film expansion plates 32, and the multiple second film expansion plates 32 are adjacent or spaced apart, and the central axes of every two second film expansion plates 32 are spaced apart, that is, any two second film expansion plates 32 are not coaxially arranged.

[0132] In this embodiment, for the position of the metal layer 12 on the wafer 1 that has not been separated, part of the second film expansion plate 32 can be driven to rise to lift up the expansion film 2 at the corresponding position, thereby separating the metal layer 12 at the corresponding position.

[0133] If there are multiple metal layers 12 on the wafer 1 that have not been separated, each of the metal layers 12 that have not been separated corresponds to a second film expansion plate 32. In the specific separation process, the second film expansion plates 32 can be driven to rise sequentially or synchronously by the driving component. The driving component can drive multiple second film expansion plates 32 to rise or fall independently, so as to control the lifting height of each second film expansion plate 32.

[0134] In the specific implementation process, if the metal layer 12 is still not completely separated after the second film expansion process is performed on the unseparated metal layer 12, the lifting height of the second film expansion plate 32 can be increased to more effectively separate the metal layer 12. Of course, if the second film expansion process is sufficient to separate the metal layer 12 within a certain height range, the lifting heights of the second film expansion plates 32 can be the same or different, and can be set according to actual conditions.

[0135] In this embodiment, not only can the metal layer 12 in most areas of the wafer 1 be subjected to the second film expansion process by using multiple second film expansion plates 32, but also the unseparated metal layer 12 in specific areas of the wafer 1 can be subjected to the second film expansion process separately to separate the grains 10 in the specific areas.

[0136] In a specific implementation process, the method for separating grains provided in any of the above embodiments further includes:

[0137] Step S4: acquiring image information of the wafer 1, and determining region information of the to-be-separated region of the wafer 1 based on the image information, wherein the metal layer 12 of the to-be-separated region has not been completely separated; and the region information includes position information.

[0138] The separation platform further includes an image collector, and the above step S4 can be performed by the image collector; the image collector can be a camera. The position information can be coordinate information.

[0139] Step S5: Based on the position information, the second film expanding plate 32 at the corresponding position is driven to be lifted up relative to the first film expanding plate 31 along the first direction Y to perform the second film expanding process.

[0140] One piece of position information corresponds to one second film expansion disk 32 .

[0141] In one embodiment, the region information further includes the separation degree of the metal layer 12; the grain separation method provided by any of the above embodiments further includes:

[0142] Step S6: Based on the separation degree of the metal layer 12, the second film expansion plate 32 at the corresponding position is driven to lift up to a preset height relative to the first film expansion plate 31 along the first direction Y; wherein, one separation degree of the metal layer 12 corresponds to one preset height; the specific corresponding relationship can be preset in advance. It should be noted that the "preset height" here refers to the lifting height of each second film expansion plate 32 relative to the first film expansion plate 31.

[0143] The method for separating the grains provided in any of the above embodiments may include one or both of step S5 and step S6 after step S4. In the specific implementation process, the above step S5 and / or step S6 may be performed by a driving component electrically connected to the image collector. The driving component may drive each second film expansion disk 32 to rise or fall independently.

[0144] The method for separating grains provided in this embodiment is to cut the wafer 1 from the side where the back side B of the wafer 1 is located to form a plurality of grooves 13, and the plurality of grooves 13 divide the wafer 1 into a plurality of grains 10 to be separated; then the wafer 1 is subjected to a film expansion treatment using an expansion film 2 attached to the front side A of the wafer 1. In this way, the separation method has the performance advantages of the plasma cutting process; and even if the front side A of the wafer 1 is provided with a metal layer 12, and the cutting process cannot cut the metal, the metal layer 12 can be further expanded by film expansion treatment after cutting, thereby dividing the wafer 1 into a plurality of single grains 10. At the same time, the separation of the metal layer 12 by film expansion treatment will not generate high temperature, thereby effectively avoiding the problem that the substrate 11 and / or the metal layer 12 cracks due to high temperature, thereby causing the entire product to fail. In addition, the cost of the film expansion treatment process is low, and it is suitable for mass production of products.

[0145] In one embodiment, a crystal grain 10 is further provided. The crystal grain 10 is separated by the above method. The area of ​​the crystal grain 10 is not greater than 9 mm 2 ; For example, 9mm 2 , 7mm 2 , 5mm 2 , 3mm 2 , 2mm 2 , 1mm 2 etc.

[0146] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for separating crystal grains, characterized in that: include: Provide wafers; The wafer has a front side and a back side facing each other, and a metal layer is arranged on the front side of the wafer; Cutting the wafer from the side where the back side of the wafer is located to form a plurality of grooves, wherein the plurality of grooves divide the wafer into a plurality of crystal grains to be separated; The wafer is subjected to a film expansion process by using an expansion film attached to the front side of the wafer to separate the plurality of dies to be separated.

2. The method for separating crystal grains according to claim 1, characterized in that: The wafer further comprises a substrate, and the metal layer is disposed on the substrate; The step of cutting the wafer from the side where the back side of the wafer is located comprises: The wafer is cut from a side of the substrate facing away from the metal layer and the cutting is stopped at least into the substrate.

3. The method for separating crystal grains according to claim 2, characterized in that: The cutting is performed from a side of the substrate facing away from the metal layer to a surface of a side of the metal layer facing the substrate.

4. The method for separating crystal grains according to claim 3, characterized in that: The wafer is subjected to a film expansion process from the side where the front surface of the wafer is located by using the expansion film to separate the metal layer.

5. The method for separating crystal grains according to any one of claims 1 to 4, characterized in that: The wafer is cut by a plasma cutting process to form a plurality of grooves.

6. The method for separating crystal grains according to any one of claims 1 to 4, characterized in that: Before cutting the wafer, the expansion film is attached to the front side of the wafer.

7. The method for separating crystal grains according to any one of claims 1 to 4, characterized in that: The wafer is subjected to multiple film expansion processes using the expansion film.

8. The method for separating crystal grains according to claim 7, characterized in that: When the wafer is subjected to film expansion processing, the wafer is fixed to a fixing component of a separation platform through the expansion film; the film expansion fixture of the separation platform is configured to lift the expansion film along a first direction; In each film expansion process, the lifting height of the film expansion fixture along the first direction is positively correlated with the number of times of the film expansion process.

9. The method for separating crystal grains according to claim 8, characterized in that: The step of performing multiple film expansion processes on the wafer using the expansion film comprises: Fixing the wafer on the separation platform through the expansion film; driving a first film expanding plate of a film expanding fixture of the separation platform to lift up the expanded film along a first direction, so that the expanded film undergoes a first film expanding process; The at least one second film expanding plate of the film expanding fixture is driven to further lift the expanded film relative to the first film expanding plate along the first direction, so that the expanded film undergoes at least one second film expanding process.

10. The method for separating crystal grains according to claim 9, characterized in that: The step of driving at least one second film expanding plate of the film expanding fixture to further lift the expanded film along the first direction comprises: According to the order in which the cross-sectional area of ​​at least one second film expanding plate of the film expanding fixture gradually decreases, the at least one second film expanding plate is driven in sequence to further lift the expanded film relative to the first film expanding plate along the first direction; wherein, the at least one second film expanding plate is coaxially arranged with the first film expanding plate; and the cross-sectional area of ​​each of the second film expanding plates is smaller than the cross-sectional area of ​​the first film expanding plate.

11. A crystal grain, characterized in that: The crystal particles are separated by the method for separating the crystal particles according to any one of claims 1 to 10.

Images