MEMS wafer segmentation method

Abstract

The invention relates to a segmentation method of an MEMS wafer. The segmentation method of the MEMS wafer comprises the steps that the MEMS wafer is provided, the MEMS wafer comprises a substrate layer and a structural layer arranged on the substrate layer, and the structural layer is provided with a sacrificial layer; the MEMS wafer is provided with a plurality of MEMS device units arranged in an array and a cutting area located between every two adjacent MEMS device units; cutting the MEMS wafer for the first time from one side, deviating from the substrate layer, of the structural layer of the MEMS wafer along the cutting area to form a first cutting groove penetrating through the structural layer and a part of the substrate layer in the thickness direction of the MEMS wafer; removing the sacrificial layer of the structural layer; and carrying out second cutting on the MEMS wafer after the sacrificial layer is removed along the first cutting groove, and segmenting each MEMS device unit to form a plurality of MEMS devices.

Description

Technical Field

[0001] The present application relates to the technical field of MEMS devices, and in particular to a method for dividing a MEMS wafer. Background Art

[0002] MEMS (Micro-electromechanical Systems), also known as micro-electromechanical systems, is based on mechanical and electrical technologies, especially micromechanics, and uses microelectronics and micromachining technologies to design, manufacture, and test a series of micro-devices within micro-nano and micro-electromechanical systems. In the manufacturing process of MEMS devices, many complex three-dimensional or supporting structures are filled with sacrificial layers. Then, the wafer is cut into individual MEMS device units through dicing, and the sacrificial layer can be further released to form the MEMS device. The sacrificial layer refers to the process of forming the cavity or movable microstructure of the micromechanical structure by first depositing the required various special structural components on the underlying film using sacrificial layer materials (commonly used are silicon oxide, polysilicon, polyimide, etc.). The sacrificial layer can be used to process and manufacture microstructures of different structures. The film is then etched away using chemical etchants or corrosive process gases without damaging the microstructures, and the upper film structure (cavity or microstructure) is obtained. Therefore, the release process is an essential step in the manufacture of MEMS devices. In the related art, the wafer is cut into individual MEMS device units, and then a sacrificial layer release process is performed. During the repeated picking, the circuit and MEMS structure of the individual MEMS device units are easily damaged, or electrostatic breakdown or the introduction of particles may occur, resulting in poor product reliability or poor quality. Summary of the Invention

[0003] The present application provides a method for dividing a MEMS wafer, which includes:

[0004] Providing a MEMS wafer, the MEMS wafer comprising a base layer and a structural layer disposed on the base layer, the structural layer having a sacrificial layer; the MEMS wafer having a plurality of MEMS device units arranged in an array and a cutting area located between every two adjacent MEMS device units;

[0005] Performing a first cutting of the MEMS wafer along the cutting area from a side of the structural layer of the MEMS wafer facing away from the base layer, to form a first cutting groove penetrating the structural layer and a portion of the base layer in a thickness direction of the MEMS wafer;

[0006] removing the sacrificial layer of the structural layer;

[0007] The MEMS wafer after the sacrificial layer is removed is cut a second time along the first cutting groove to separate each MEMS device unit to form a plurality of MEMS devices.

[0008] In some embodiments, before performing a first cutting of the MEMS wafer along the cutting region from a side of the structure layer of the MEMS wafer facing away from the base layer, the method includes:

[0009] A protective adhesive layer is provided on a side of the structural layer of the MEMS wafer facing away from the base layer.

[0010] In some embodiments, after providing a protective adhesive layer on a side of the structure layer of the MEMS wafer facing away from the base layer, and before performing a first cut on the MEMS wafer along the cutting region from the side of the structure layer of the MEMS wafer facing away from the base layer, the method includes:

[0011] The MEMS wafer is fixed on a cutting table through a first adhesive layer and a first supporting fixing ring.

[0012] In some embodiments, after cutting the MEMS wafer for the first time along the cutting region from a side of the structure layer of the MEMS wafer facing away from the base layer, and before removing the sacrificial layer of the structure layer, the method includes:

[0013] The MEMS wafer after the first cutting is cleaned and the protective adhesive layer is removed.

[0014] In some embodiments, after the MEMS wafer is cut for the first time along the cutting region from the side of the structural layer of the MEMS wafer facing away from the base layer, and before the MEMS wafer is cleaned after the first cutting and the protective adhesive layer is removed, the method includes:

[0015] Remove the MEMS wafer from the first adhesive layer, and remove the first supporting fixing ring and the first adhesive layer from the cutting table;

[0016] The cleaning of the MEMS wafer after the first cutting and removing the protective adhesive layer includes:

[0017] The MEMS wafer removed from the first adhesive layer is placed in a cleaning tank for cleaning and the protective adhesive layer is removed.

[0018] In some embodiments, after removing the sacrificial layer of the structural layer and before cutting the MEMS wafer for a second time along the first cutting groove after removing the sacrificial layer, the method includes:

[0019] The MEMS wafer is fixed on a cutting table through a second adhesive layer and a second supporting fixing ring; the side of the base layer of the MEMS wafer facing away from the structural layer faces the cutting table.

[0020] In some embodiments, after the MEMS wafer is cut for the first time along the cutting region from the side of the structural layer of the MEMS wafer facing away from the base layer, and before the MEMS wafer is cleaned after the first cutting and the protective adhesive layer is removed, the method includes:

[0021] Remove the MEMS wafer, the first adhesive layer fixing the MEMS wafer, and the first supporting fixing ring from the cutting table as a whole;

[0022] The cleaning of the MEMS wafer after the first cutting and removing the protective adhesive layer includes:

[0023] The MEMS wafer, the first adhesive layer fixing the MEMS wafer, and the first supporting fixing ring are placed in a cleaning tank for cleaning and the protective adhesive layer is removed.

[0024] In some embodiments, after removing the sacrificial layer of the structural layer and before cutting the MEMS wafer for a second time along the first cutting groove after removing the sacrificial layer, the method includes:

[0025] The MEMS wafer with the protective adhesive layer removed, the first adhesive layer and the first supporting fixing ring are fixed on the cutting table again.

[0026] In some embodiments, cutting the MEMS wafer for the second time along the first cutting groove after removing the sacrificial layer comprises:

[0027] Performing laser blind cutting on the MEMS wafer after removing the sacrificial layer along the first cutting groove;

[0028] Providing an expansion force to the adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer, so as to separate the MEMS device;

[0029] The adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer is removed.

[0030] In some embodiments, after cleaning the MEMS wafer after the first dicing and removing the protective adhesive layer, the method includes:

[0031] The MEMS wafer with the protective adhesive layer removed is subjected to a spin-drying process.

[0032] In some embodiments, a cleaning solution containing an alcohol solution accounting for more than 50% by volume is used to clean the MEMS wafer after the first cutting and remove the protective adhesive layer.

[0033] In some embodiments, the first cutting is performed using a mechanical cutting technique or a laser surface cutting technique.

[0034] In some embodiments, the MEMS wafer has a bottom surface located on a side of the base layer facing away from the structural layer, and a distance between a bottom of the first cutting groove and the bottom surface of the MEMS wafer is less than two-thirds of the thickness of the MEMS wafer.

[0035] The MEMS wafer segmentation method provided in the embodiment of the present application forms a first cutting groove in the cutting area after the first cutting, and cuts the structural layer and cuts a part of the thickness of the base layer, thereby removing the sacrificial layer, and then performing a second cutting along the cutting area on the incompletely segmented base layer, thereby achieving the release and removal of the wafer-level sacrificial layer, which is beneficial to improving the production efficiency of MEMS wafer segmentation and MEMS devices. Compared with the method of removing the sacrificial layer after cutting the wafer into a single MEMS device unit, it can reduce or even avoid the damage to the circuit and MEMS structure of the single MEMS device unit during repeated picking, as well as the occurrence of poor product reliability or quality caused by electrostatic breakdown or the introduction of particles, that is, avoiding the repeated picking and turnover of a single MEMS device to release the sacrificial layer, reducing the introduction of abnormalities, and improving the reliability and quality of the MEMS device formed after wafer segmentation. At the same time, it can also avoid the introduction of a single release carrier, greatly reducing the difficulty of the process.

[0036] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A flowchart of a method for dividing a MEMS wafer provided in one embodiment of the present application;

[0039] Figures 2 to 11 A schematic structural diagram corresponding to different preparation process stages of a MEMS wafer segmentation method provided in one embodiment of the present application;

[0040] Figure 12 A schematic diagram of a MEMS wafer fixed by a first adhesive layer and a first supporting fixing ring provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0042] The present application provides a method for dividing a MEMS wafer, which includes providing a MEMS wafer, wherein the MEMS wafer includes a base layer and a structural layer arranged on the base layer, the structural layer having a sacrificial layer; the MEMS wafer has a plurality of MEMS device units arranged in an array and a cutting area located between each two adjacent MEMS device units; performing a first cutting on the MEMS wafer along the cutting area from a side of the structural layer of the MEMS wafer away from the base layer to form a first cutting groove that passes through the structural layer and a portion of the base layer in a thickness direction of the MEMS wafer; removing the sacrificial layer of the structural layer; and performing a second cutting on the MEMS wafer after the sacrificial layer is removed along the first cutting groove to separate each MEMS device unit to form a plurality of MEMS devices. The above-mentioned method for dividing MEMS wafers forms a first cutting groove in the cutting area after the first cutting, and cuts the structural layer and a partial thickness of the base layer, thereby removing the sacrificial layer, and then performing a second cutting on the incompletely divided base layer along the cutting area, thereby achieving the release and removal of the wafer-level sacrificial layer, which is beneficial to improving the production efficiency of MEMS wafer division and MEMS devices. Compared with the method of removing the sacrificial layer after dividing the wafer into a single MEMS device unit, it can reduce or even avoid damage to the circuit and MEMS structure of a single MEMS device unit during repeated picking, as well as electrostatic breakdown or the introduction of particles, which may cause poor product reliability or quality. That is, it avoids the repeated picking and turnover of a single MEMS device to release the sacrificial layer, reduces the introduction of abnormalities, and is beneficial to improving the reliability and quality of the MEMS device formed after wafer cutting. At the same time, it can also avoid the introduction of a single release carrier, greatly reducing the difficulty of the process.

[0043] The following is combined with Figures 1 to 12 The MEMS wafer segmentation method provided in this application is described in detail.

[0044] Please refer to Figure 1 , and when necessary, combine Figures 2 to 12As shown, the present application provides a method for dividing a MEMS wafer, which comprises the following steps S101 to S107:

[0045] In step S101, a MEMS wafer is provided, which comprises a substrate layer and a structure layer disposed on the substrate layer, the structure layer having a sacrificial layer; the MEMS wafer has a plurality of arrayed MEMS device units and a cutting region between each two adjacent MEMS device units.

[0046] In step S103, the MEMS wafer is first cut along the cutting region from the side of the structure layer away from the substrate layer, forming a first cutting groove penetrating the structure layer and part of the substrate in the thickness direction of the MEMS wafer.

[0047] In step S105, the sacrificial layer of the structure layer is removed.

[0048] In step S107, the MEMS wafer after the removal of the sacrificial layer is second cut along the first cutting groove, dividing each MEMS device unit to form a plurality of MEMS devices.

[0049] As Figure 2 As shown in step S101, a MEMS wafer 100 is provided, which comprises a substrate layer 10 and a structure layer 20 disposed on the substrate layer 10, the structure layer having a sacrificial layer. The MEMS wafer 100 has a plurality of arrayed MEMS device units 101 and a cutting region 102 between each two adjacent MEMS device units 101.

[0050] In some embodiments, the structure layer 20 comprises a MEMS device layer and a readout circuit layer. In other embodiments, the structure layer can also comprise a MEMS device layer without a readout circuit layer.

[0051] In some embodiments, the substrate layer 10 is a substrate layer, such as a substrate layer formed of a silicon-based material. In other embodiments, the substrate layer can also be a substrate layer and an external metal layer or other material layer disposed on the side of the substrate layer away from the structure layer.

[0052] It can be understood that the structure layer of the cutting region 102 actually does not set the corresponding structure and sacrificial region of the MEMS device, but is a material layer formed together in the process of making the MEMS device.

[0053] As Figure 3As shown, before performing a first cutting of the MEMS wafer 100 along the cutting region 102 from the side of the structure layer 20 of the MEMS wafer 100 facing away from the base layer 10 in step S103, the method may include the following step S102:

[0054] In step S102 , a protective adhesive layer 200 is provided on a side of the structure layer 20 of the MEMS wafer 100 facing away from the base layer 10 .

[0055] The protective adhesive layer 200 can be made of a photoresist material and can protect the structural layer 20 , thereby reducing or even preventing silicon slag or other debris or impurities 104 generated by cutting from entering the structural layer 20 during the subsequent first cutting.

[0056] After step S102, the following can be formed: Figure 3 The wafer assembly 1001 of the MEMS wafer 100 shown in FIG. 1 is provided with a protective adhesive layer 200 on the side of the structural layer 20 facing away from the base layer 10 .

[0057] like Figure 4 , and combined with Figure 12 As shown, after providing a protective adhesive layer on the side of the structure layer 20 of the MEMS wafer facing away from the base layer 10 in step S102, and before performing a first cutting of the MEMS wafer 100 along the cutting region 102 from the side of the structure layer of the MEMS wafer 100 facing away from the base layer in step S103, the method may include the following step S104:

[0058] In step S104 , the MEMS wafer 100 is fixed on the cutting table 700 via the first adhesive layer 300 and the first supporting fixing ring 400 .

[0059] The side of the base layer 10 of the MEMS wafer 100 facing away from the structural layer 20 faces the cutting table 700. The first adhesive layer 300 has a first wafer attachment area 301 located in the middle and a first fixed support area 302 located outside the first wafer attachment area 301. The side of the base layer 10 of the MEMS wafer 100 facing away from the structural layer 20 faces the first adhesive layer 300 and is located in the first wafer attachment area 301. The first supporting fixing ring 400 is located in the first fixed support area 302 to secure the first adhesive layer 300 to the cutting table 700.

[0060] The first adhesive layer 300 may be a photosensitive adhesive film layer, such as a UV film, which can be removed by irradiation with light when it is needed. The first supporting fixing ring 400 may be a supporting steel ring or a supporting ring.

[0061] It should be noted that step S104 may be performed after step S102 in which a protective adhesive layer 200 is provided on a side of the structural layer of the MEMS wafer 100 facing away from the base layer.

[0062] Combine Figure 12 As shown, for the MEMS wafer 100, a protective adhesive layer 200 is provided on the side of the structural layer 20 facing away from the base layer 10 to form a wafer assembly 1001. In the step S104, the wafer assembly 1001 is specifically fixed on the cutting table 700 through the first adhesive layer 300 and the first supporting fixing ring 400, wherein the protective adhesive layer 200 is located on the side of the MEMS wafer 100 facing away from the first adhesive layer 300.

[0063] Of course, in some other embodiments, step S104 may also be performed before step S102 of providing a protective adhesive layer on the side of the structural layer of the MEMS wafer facing away from the base layer.

[0064] like Figure 5 and Figure 6 As shown, in step S103, the MEMS wafer 100 is cut for the first time along the cutting area 102 from the side of the structural layer 20 of the MEMS wafer 100 away from the base layer 10, forming a first cutting groove 103 that passes through the structural layer 20 and part of the base layer 10 in the thickness direction T of the MEMS wafer 100.

[0065] In some embodiments, the first cutting is performed using a mechanical cutting technique. Figure 5 Schematically, a cutting blade 500 may be used to cut the MEMS wafer 100 for the first time along the cutting region 102 from the side of the structure layer 20 of the MEMS wafer 100 facing away from the base layer 10 , thereby forming a first cutting groove 103 .

[0066] In other embodiments, the first cutting adopts laser surface cutting technology to cut. Of course, the first cutting can also adopt other technologies that can cut the structural layer to cut.

[0067] After step S103 , the structural layer 20 at the cutting area 102 can be cut open, and a partial thickness of the base layer 10 can be cut, so that the base layer portion below the first cutting groove 103 can be better cut during the subsequent second cutting.

[0068] In some embodiments, the MEMS wafer 100 has a bottom surface S located on a side of the base layer 10 facing away from the structural layer 20 , such as Figure 5 The surface of the MEMS wafer 100 is shown facing the first adhesive layer 300 .

[0069] After step S103 , in the formed structure, the distance h between the bottom of the first cutting groove 103 and the bottom surface S of the MEMS wafer 100 is less than two-thirds of the thickness of the MEMS wafer.

[0070] For example, in some embodiments, the distance h between the bottom of the first cutting groove 103 and the bottom surface S of the MEMS wafer 100 may be 100 μm-300 μm.

[0071] Combine Figure 7 As shown, after the MEMS wafer 100 is cut for the first time along the cutting region 102 from the side of the structural layer of the MEMS wafer 100 facing away from the base layer in step S103, and before the sacrificial layer of the structural layer is removed in step S105, the method may include the following step S106:

[0072] In step S106, the MEMS wafer 100 after the first cutting is cleaned and the protective adhesive layer 200 is removed to obtain the following Figure 7 The intermediate structure shown.

[0073] Through step S106 , debris such as silicon slag or impurities 104 attached to the surface of the MEMS wafer 100 after the first cutting can be removed, and the protective adhesive layer 200 can also be removed.

[0074] If the protective adhesive layer 200 is a photosensitive adhesive film layer, such as a UV film, the protective adhesive layer 200 can be removed by irradiation with light.

[0075] In step S106 , the protective adhesive layer 200 may be removed first, and then the MEMS wafer 100 after the first cutting is cleaned, or vice versa.

[0076] In some embodiments, after the MEMS wafer 100 is cut for the first time along the cutting area 102 from the side of the structural layer 20 of the MEMS wafer 100 facing away from the base layer 10 in step S103, and before the MEMS wafer 100 is cleaned after the first cut and the protective adhesive layer 200 is removed in step S106, the method includes the following step S1081:

[0077] In step S1081 , the MEMS wafer 100 , the first adhesive layer 300 fixing the MEMS wafer 100 , and the first supporting and fixing ring 400 are removed from the cutting table 700 .

[0078] Accordingly, in step S106 , cleaning the MEMS wafer 100 after the first cutting and removing the protective adhesive layer 200 may include the following step S1061 :

[0079] In step S1061, the MEMS wafer 100 and the first adhesive layer 300 and the first bearing fixing ring 400 fixing the MEMS wafer 100 are placed in a cleaning tank (not shown) for cleaning and removing the protective adhesive layer 200.

[0080] In some embodiments, after the first cutting of the MEMS wafer 100 in step S103, the method further comprises the following step S1082 before the cleaning and removing of the protective adhesive layer 200 in step S106:

[0081] In step S1082, the first cutting MEMS wafer 100 is removed from the first adhesive layer 300, and the first bearing fixing ring 400 and the first adhesive layer 300 are removed from the cutting table 700.

[0082] Correspondingly, the cleaning and removing of the protective adhesive layer 200 in step S106 can comprise the following step S1062:

[0083] In step S1062, the MEMS wafer 100 removed from the first adhesive layer 300 is placed in a cleaning tank for cleaning and removing the protective adhesive layer 200.

[0084] In some embodiments, after the cleaning and removing of the protective adhesive layer 200 in step S106, the method can comprise the following step S109:

[0085] In step S109, the MEMS wafer 100 cleaned and removing the protective adhesive layer 200 is subjected to a spin-drying treatment.

[0086] The spin-drying treatment can be performed by a spin-drying device in the process of manufacturing MEMS devices or wafers.

[0087] In some embodiments, the spin-drying treatment in step S109 can be omitted. Correspondingly, the cleaning solution used in step S106 can comprise an alcohol solution with a volume ratio of 50% or more. In particular, for the first cutting MEMS wafer 100 with cracks and fragile pieces, at least 50% of the cleaning solution can be alcohol solution. After cleaning, the alcohol evaporates and the MEMS wafer 100 is naturally dried.

[0088] Further, in step S105, the sacrificial layer (not shown) of the structure layer is removed.

[0089] In step S105, a wafer releasing process such as a chemical etching agent or a corrosion process gas can be used to etch away the sacrificial layer without damaging the microstructure, and then a thin film structure of the MEMS device layer is obtained, i.e. a microstructure with a cavity formed in the space of the original sacrificial layer in the MEMS device layer.

[0090] As shown in FIG. 1 1, in step S107, the MEMS wafer 100 after removing the sacrificial layer is cut again along the first cutting groove 103 to separate each MEMS device unit 101, and a plurality of MEMS devices are formed. Figures 8 to 11 The second cutting can use a laser stealth cutting technology. Compared with mechanical devices or laser surface cutting, the laser stealth cutting technology produces less silicon slag and other debris or impurities 104, which can effectively reduce or even avoid the impact on the formed MEMS device.

[0091] In some embodiments, for removing the MEMS wafer 100 and the first adhesive layer 300 and the first bearing fixing ring 400 fixing the MEMS wafer 100 as a whole from the cutting table 700, placing the MEMS wafer 100 and the first adhesive layer 300 and the first bearing fixing ring 400 fixing the MEMS wafer 100 as a whole in a cleaning tank (not shown) to clean and remove the protective adhesive layer 200 (i.e. the implementation corresponding to step S1081 and step S1061), the first adhesive layer 300 and the first bearing fixing ring 400 fixing the MEMS wafer 100 as a whole can be directly set again on the cutting table 700, so as to perform the steps of step S107. That is, the MEMS wafer and the first adhesive layer and the first bearing fixing ring after removing the protective adhesive layer 200 are fixed again on the cutting table.

[0092] In other embodiments, for removing the MEMS wafer 100 from the first adhesive layer 300 and the first bearing fixing ring 400, placing the MEMS wafer 100 removed from the first adhesive layer 300 and the first bearing fixing ring 400 in a cleaning tank to clean and remove the protective adhesive layer 200 (i.e. the implementation corresponding to step S1082 and step S1062), after removing the sacrificial layer of the structure layer in step S105, before cutting the MEMS wafer 100 after removing the sacrificial layer again along the first cutting groove 103 in step S107, the method can include the following step S110:

[0093] In step S110, the MEMS wafer 100 is fixed on the cutting table 700 by a second adhesive layer (not shown) and a second bearing fixing ring (not shown).

[0094] ​

[0095] The side of the base layer of the MEMS wafer 100 facing away from the structural layer faces the cutting table 700; wherein, the second adhesive layer has a second wafer mounting area located in the middle and a second fixed support area located outside the second wafer mounting area, and the side of the base layer of the MEMS wafer 100 facing away from the structural layer faces the second adhesive layer and is arranged in the second wafer mounting area, and the second supporting fixing ring is arranged in the second fixed support area to fix the second adhesive layer on the cutting table 700.

[0096] The material and specific structure of the second adhesive layer are similar to those of the first adhesive layer 300 . For details, please refer to the relevant description of the first adhesive layer 300 , which will not be repeated here.

[0097] The second load-bearing fixing ring and the first load-bearing fixing ring 400 can be the same load-bearing fixing ring or similar load-bearing fixing rings. Please refer to the relevant description of the first load-bearing fixing ring 400 and will not be repeated here.

[0098] like Figures 8 to 11 As shown, after the second cutting of the MEMS wafer 100 after the sacrificial layer is removed along the first cutting groove 103 , step S107 may include the following steps S1071 and S1073 :

[0099] like Figure 8 and Figure 9 In step S1071, laser blind cutting is performed on the MEMS wafer 100 after the sacrificial layer is removed along the first cutting groove 103. Figure 8 As shown in FIG600, a laser hidden cutting is performed to form a portion of the base layer at the bottom of the first cutting groove 103 which is not penetrated by the first cutting groove 103. Figure 9 The modified layer after implicit cutting is shown.

[0100] like Figure 10 As shown, in step S1073 , an expansion force F is provided to the first adhesive layer 300 corresponding to the side of the base layer of the MEMS wafer 100 facing away from the structural layer, so that the MEMS device is separated.

[0101] Here the size of F can be set more specifically as needed.

[0102] It is understandable that if a second adhesive layer is used in step S107, in step S110, an expansion force is provided to the second adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer, so that the MEMS device is separated.

[0103] In step S1073 , the first adhesive layer 300 corresponding to the side of the base layer of the MEMS wafer 100 facing away from the structural layer is removed.

[0104] It is understandable that if a second adhesive layer is used in step S107 , then in step S120 , the second adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer is removed.

[0105] After step S120, multiple Figure 11 The MEMS device 1000 is shown.

[0106] The MEMS device 1000 may be a single body structure corresponding to the MEMS device unit 101 .

[0107] It should be noted that MEMS wafer dicing can be performed using both mechanical and laser cutting. Mechanical dicing, similar to the principle of an everyday saw, is destructive and requires grinding away a portion of the cut piece. Therefore, it can only be performed before the release process, with the sacrificial layer released after dicing into individual MEMS devices. Placing individual MEMS devices on a carrier and ensuring high flatness and temperature uniformity on the carrier are challenging processes. Repeated handling can easily damage the MEMS device circuitry and structure, cause electrostatic breakdown, or introduce particles, resulting in poor product reliability or quality. Furthermore, due to the front-end support of the MEMS device, some metal is located in the dicing area. Laser cutting can be categorized as surface cutting and internal laser cutting. Surface laser cutting focuses laser energy onto the surface to cut the material, generating a significant amount of particle contamination. Internal laser cutting, on the other hand, uses a laser beam of a specific wavelength focused through a lens to create a localized deformation layer (a modified layer) within the wafer. Compared to surface laser cutting, internal laser cutting does not generate significant particle contamination. However, the laser stealth cutting process cannot penetrate metal, and its efficiency in cutting thicker wafers (for example, those thicker than 300um) is extremely low.

[0108] Based on this, the MEMS wafer segmentation method provided by this application can be implemented by two cuttings. The first cutting can be done by mechanical cutting and laser surface cutting to cut the structural layer. The particles generated by the first cutting can be cleaned off, and then a second cutting can be done in the cutting area. The second cutting can be done by laser invisible cutting, so that a modified layer can be formed below the first cutting groove. After the modified layer is formed, a similar Figure 10 As shown, external force is used to guide the cracks to the surface and bottom of the wafer, thereby separating the wafer into MEMS devices corresponding to the MEMS device units.

[0109] In this application, the structural embodiments and method embodiments may complement each other if they do not conflict.

[0110] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The terms "plurality" and "several" refer to two or more, unless otherwise clearly defined.

[0111] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0112] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for dividing a MEMS wafer, characterized in that: include: Providing a MEMS wafer, the MEMS wafer comprising a base layer and a structural layer disposed on the base layer, the structural layer having a sacrificial layer; The MEMS wafer has a plurality of MEMS device units arranged in an array and a cutting area located between every two adjacent MEMS device units; Performing a first cutting of the MEMS wafer along the cutting area from a side of the structural layer of the MEMS wafer facing away from the base layer, to form a first cutting groove penetrating the structural layer and a portion of the base layer in a thickness direction of the MEMS wafer; removing the sacrificial layer of the structural layer; The MEMS wafer after the sacrificial layer is removed is cut a second time along the first cutting groove to separate each MEMS device unit to form a plurality of MEMS devices.

2. The method for dividing a MEMS wafer according to claim 1, wherein: Before cutting the MEMS wafer for the first time along the cutting region from the side of the structure layer of the MEMS wafer facing away from the base layer, the method includes: A protective adhesive layer is provided on a side of the structural layer of the MEMS wafer facing away from the base layer.

3. The method for dividing a MEMS wafer according to claim 2, wherein: After providing a protective adhesive layer on a side of the structural layer of the MEMS wafer facing away from the base layer, and before performing a first cutting of the MEMS wafer along the cutting area from the side of the structural layer of the MEMS wafer facing away from the base layer, the method includes: The MEMS wafer is fixed on a cutting table through a first adhesive layer and a first supporting fixing ring; the side of the base layer of the MEMS wafer facing away from the structural layer faces the cutting table.

4. The method for dividing a MEMS wafer according to claim 3, wherein: After cutting the MEMS wafer for the first time along the cutting region from a side of the structural layer of the MEMS wafer facing away from the base layer, and before removing the sacrificial layer of the structural layer, the method includes: The MEMS wafer after the first cutting is cleaned and the protective adhesive layer is removed.

5. The method for dividing a MEMS wafer according to claim 4, wherein: After the MEMS wafer is cut for the first time along the cutting area from the side of the structural layer of the MEMS wafer facing away from the base layer, and before the MEMS wafer is cleaned after the first cutting and the protective adhesive layer is removed, the method includes: Remove the MEMS wafer from the first adhesive layer, and remove the first supporting fixing ring and the first adhesive layer from the cutting table; The cleaning of the MEMS wafer after the first cutting and removing the protective adhesive layer includes: The MEMS wafer removed from the first adhesive layer is placed in a cleaning tank for cleaning and the protective adhesive layer is removed.

6. The method for dividing a MEMS wafer according to claim 5, wherein: After removing the sacrificial layer of the structural layer and before cutting the MEMS wafer for the second time along the first cutting groove after removing the sacrificial layer, the method includes: The MEMS wafer is fixed on a cutting table through a second adhesive layer and a second supporting fixing ring; the side of the base layer of the MEMS wafer facing away from the structural layer faces the cutting table.

7. The method for dividing a MEMS wafer according to claim 4, wherein: After the MEMS wafer is cut for the first time along the cutting area from the side of the structural layer of the MEMS wafer facing away from the base layer, and before the MEMS wafer is cleaned after the first cutting and the protective adhesive layer is removed, the method includes: Remove the MEMS wafer, the first adhesive layer fixing the MEMS wafer, and the first supporting fixing ring from the cutting table as a whole; The cleaning of the MEMS wafer after the first cutting and removing the protective adhesive layer includes: The MEMS wafer, the first adhesive layer fixing the MEMS wafer, and the first supporting fixing ring are placed in a cleaning tank for cleaning and the protective adhesive layer is removed.

8. The method for dividing a MEMS wafer according to claim 7, wherein: After removing the sacrificial layer of the structural layer and before cutting the MEMS wafer for the second time along the first cutting groove after removing the sacrificial layer, the method includes: The MEMS wafer with the protective adhesive layer removed, the first adhesive layer and the first supporting fixing ring are fixed on the cutting table again.

9. The method for dividing a MEMS wafer according to claim 6 or 8, wherein: The second cutting of the MEMS wafer after removing the sacrificial layer along the first cutting groove includes: Performing laser blind cutting on the MEMS wafer after removing the sacrificial layer along the first cutting groove; Providing an expansion force to the adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer, so as to separate the MEMS device; The adhesive layer corresponding to the side of the base layer of the MEMS wafer facing away from the structural layer is removed.

10. The method for dividing a MEMS wafer according to claim 4, wherein: After cleaning the MEMS wafer after the first cutting and removing the protective adhesive layer, the method includes: The MEMS wafer with the protective adhesive layer removed is subjected to a spin-drying process.

11. The method for dividing a MEMS wafer according to claim 4, wherein: The MEMS wafer after the first cutting is cleaned by using a cleaning solution in which the volume of the alcohol solution accounts for more than 50% and the protective adhesive layer is removed.

12. The method for dividing a MEMS wafer according to claim 1, wherein: The first cutting adopts mechanical cutting technology or laser surface cutting technology.

13. The method for dividing a MEMS wafer according to claim 1, wherein: The MEMS wafer has a bottom surface located on a side of the base layer facing away from the structural layer, and a distance between a bottom of the first cutting groove and the bottom surface of the MEMS wafer is less than two-thirds of the thickness of the MEMS wafer.

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