A micro-electro-mechanical system composite wafer
By setting a protective layer on the microelectromechanical system composite wafer to maintain a distance from the diaphragm, and setting windows and ventilation holes at appropriate locations, the problem of easy damage to the diaphragm during the thinning process is solved, and the product yield is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING BOE SENSOR TECH CO LTD
- Filing Date
- 2024-03-28
- Publication Date
- 2026-07-24
AI Technical Summary
During the wafer thinning process of microelectromechanical systems (MEMS), the diaphragm is prone to damage, which can lead to wafer damage and affect product yield.
In the grinding process of microelectromechanical system composite wafers, a protective layer is set on the wafer surface, the protective layer is kept at a certain distance from the diaphragm, and windows and ventilation holes are set at appropriate positions to protect the diaphragm and reduce the probability of damage.
It effectively reduces the probability of diaphragm damage and improves the product yield of MEMS composite wafers.
Smart Images
Figure CN120717404B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, and in particular to a microelectromechanical system (MEMS) composite wafer. Background Technology
[0002] Microelectromechanical system (MEMS) wafers are generally quite thick after fabrication. When using thick MEMS wafers for packaging, the wire bonding arcs are larger and occupy a larger horizontal area, which places higher demands on subsequent production and the technical skills of the personnel. Furthermore, the height of MEMS wafers after packaging is also relatively high, resulting in them occupying more space in the end product. Therefore, it is necessary to thin the MEMS wafers.
[0003] However, the surface of a microelectromechanical system (MEMS) wafer contains a thin and brittle diaphragm, which is prone to cracking and breakage under external forces, ultimately damaging the wafer. Therefore, avoiding diaphragm damage during the wafer thinning process in MEMS wafer manufacturing is a pressing issue that needs to be addressed. Summary of the Invention
[0004] In view of the above problems, this application provides a microelectromechanical system (MEMS) composite wafer, which can effectively reduce the probability of diaphragm damage during the grinding process of the MEMS composite wafer, thereby improving the product yield of the MEMS composite wafer.
[0005] A first aspect of this application provides a microelectromechanical system (MEMS) composite wafer, comprising: a MEMS wafer body including a plurality of die arrays arranged along a first direction, the die array including a plurality of dies arranged along a second direction, each die including a groove, the first direction being perpendicular to the second direction; a diaphragm covering the grooves in a third direction, the third direction being perpendicular to both the first and second directions; and a protective layer disposed between the grooves; wherein, in the first and second directions, the spacing L1 between the protective layer and the grooves satisfies 0 μm < L1 ≤ 500 μm; in the third direction, the size of the protective layer is larger than the size of the diaphragm, and the size difference L2 satisfies 0 mm < L2 ≤ 1 mm.
[0006] In some possible implementations, the groove includes a first groove and a second groove; the protective layer has a first window and a second window to expose the first groove and the second groove, respectively.
[0007] In some possible implementations, the groove includes a first groove and a second groove; in the third direction, the protective layer covers the first groove and the second groove, and the protective layer is provided with at least one ventilation hole, the at least one ventilation hole being opposite to the first groove and / or the second groove.
[0008] In some possible implementations, the grain further includes a pad region; in the third direction, the protective layer avoids the pad region.
[0009] In some possible implementations, the material of the protective layer is at least one of organic materials and inorganic non-metallic materials.
[0010] In one possible implementation, the bonding strength P between the protective layer and the microelectromechanical system wafer body is 0 < P ≤ 30 MPa.
[0011] In some possible implementations, the strength of the protective layer is greater than or equal to 50 MPa.
[0012] In one possible implementation, the protective layer has positioning holes that are positioned with respect to the microelectromechanical system wafer body.
[0013] In some possible implementations, the protective layer has visual dots, the shape of which includes at least one of circles, crosses, or matrices. Attached Figure Description
[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.
[0015] Figure 1 This is a partial structural schematic diagram of a MEMS composite wafer according to an embodiment of this application; Figure 2 This is a cross-sectional view of a MEMS composite wafer according to an embodiment of this application; Figure 3 This is a schematic diagram of the grain structure according to an embodiment of this application; Figure 4 This is a left-side cross-sectional view of a MEMS composite wafer according to another embodiment of this application; Figure 5 This is a cross-sectional view of a MEMS composite wafer according to another embodiment of this application; Figure 6 This is a schematic diagram of the grain structure according to another embodiment of this application; Figure 7 This is a partial structural schematic diagram of a MEMS composite wafer according to another embodiment of this application.
[0016] Figure label: MEMS composite wafer-1, MEMS wafer body-11, separator-12, protective layer-13; Grain-111, Groove-112, Pad Area-114, Corner-115, First Window-131, Second Window-132, Ventilation Hole-133, Positioning Hole-134; First groove-1121, second groove-1122; First direction - X, second direction - Y, third direction - Z. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0018] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a specific range. Ranges defined in this way include endpoint values and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is also expected that ranges of 60-110 and 80-120 are also included. Furthermore, if the minimum range values are listed as 1 and 2, and the maximum range values are listed as 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer greater than or equal to 2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0019] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined with each other to form new technical solutions.
[0020] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.
[0021] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, “at least one” and “one or more” refer to one, two, or more than two. The term “and / or” is used to describe the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can indicate: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.
[0022] References to "one embodiment," "some embodiments," "one example," or "some examples" used in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.
[0023] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0024] Micro-Electro-Mechanical Systems (MEMS) is a high-tech field based on microelectronics and microfabrication technologies. MEMS technology integrates mechanical components, drive components, electronic control systems, and digital processing systems into a single miniature unit. MEMS devices offer numerous advantages, including miniaturization, intelligence, actuation capabilities, integrability, good process compatibility, and low cost. The development of MEMS technology has opened up a completely new technological field and industry. Microsensors, microactuators, microcomponents, micromechanical optical devices, vacuum microelectronic devices, and power electronic devices fabricated using MEMS technology have broad application prospects in aerospace, automotive, and biomedical fields.
[0025] As mentioned earlier, MEMS wafers have certain size requirements for practical applications. However, with current manufacturing processes, grinding the back of the MEMS wafer to meet these size requirements can damage the surface membrane, leading to wafer breakage.
[0026] In view of this, this application provides a MEMS composite wafer that can reduce the probability of diaphragm damage when performing back-side grinding on the MEMS composite wafer to reduce its thickness.
[0027] The MEMS composite wafer of this application will be described in detail below with reference to the accompanying drawings.
[0028] Figure 1 This is a partial structural schematic diagram of a MEMS composite wafer according to one embodiment of this application. Figure 1 As shown, the MEMS composite wafer 1 includes a MEMS wafer body 11, the MEMS wafer body 11 includes a plurality of grain arrays arranged along a first direction X, the grain arrays include a plurality of grains 111 arranged along a second direction Y, and the grains 111 include grooves 112, the first direction X is perpendicular to the second direction Y.
[0029] As shown in the figure, the first direction X can also be called the width direction of MEMS composite wafer 1, and the second direction Y can also be called the width direction of MEMS composite wafer 1.
[0030] It should be understood that the MEMS wafer body 11 includes multiple grain arrays arranged along the first direction X, and the grain arrays include multiple grains 111 arranged along the second direction Y. That is, the MEMS composite wafer 1 has multiple grains 111 in both the first direction X and the second direction Y.
[0031] It should be understood that the grain 111 having grooves 112 means that each grain 111 has grooves 112.
[0032] It should be understood that die 111 can also be called die 111 or chip 111.
[0033] Figure 2 This is a cross-sectional view of a MEMS composite wafer according to one embodiment of this application. Figure 1 and Figure 2 As shown, the MEMS composite wafer 1 includes a diaphragm 12, which covers a groove 112 in a third direction Z, perpendicular to the first direction X and the second direction Y.
[0034] The third direction Z can also be referred to as the height or thickness of the MEMS composite wafer 1. The first direction X is perpendicular to the second direction Y, and the third direction Z is perpendicular to the first direction X and the second direction Y. This means that the first direction X is perpendicular to the plane formed by the second direction Y and the third direction Z, the second direction Y is perpendicular to the plane formed by the first direction X and the third direction Z, and the third direction Z is perpendicular to the plane formed by the first direction X and the second direction Y.
[0035] The MEMS wafer body 11 has multiple dies 111 in the first direction X and the second direction Y. Therefore, in the third direction Z, the diaphragm 12 covers the grooves 112 of the dies 111, meaning that each groove 112 is covered by the diaphragm 12, while the areas of each die 111 that are not grooves 112 are not covered by the diaphragm 12.
[0036] Specifically, the diaphragm 12 here is a silicon material with a thickness ≤ 5 μm. In the MEMS composite wafer 1 described in this application, the diaphragm 12 senses external pressure, then converts the pressure signal into an electrical signal through a circuit, and finally transmits the electrical signal through the pad area described below.
[0037] Please continue to refer to Figure 1 and Figure 2 The MEMS composite wafer 1 also includes a protective layer 13; the protective layer 13 is disposed between the grooves 112.
[0038] It should be understood that each grain 111 has a groove 112. The protective layer 13 is disposed between the grooves 112, meaning that the groove 112 of each grain 111 is provided with a protective layer 13 between the grooves 112 of other grains 111.
[0039] Specifically, in the first direction X and the second direction Y, the distance L1 between the protective layer 13 and the groove 112 satisfies 0μm<L1≤500μm; in the third direction Z, the size of the protective layer 13 is larger than the size of the diaphragm 12, and the size difference L2 satisfies 0mm<L2≤1mm.
[0040] The protective layer 13 is disposed between different grooves 112. Therefore, in the first direction X and the second direction Y, the distance L1 between the protective layer 13 and the groove 112 must satisfy 0μm<L1≤500μm.
[0041] It should be understood that since the diaphragm 12 covers the groove 112, L1 can be described as the distance between the protective layer 13 and the groove 112, or as the distance between the protective layer 13 and the diaphragm 12.
[0042] In the above scheme, the MEMS composite wafer 1 includes a MEMS wafer body 11, a diaphragm 12 covering the grooves 112 of the MEMS wafer body 11, and a protective layer 13 disposed between different grooves 112. By setting the protective layer 13 on the MEMS composite wafer 1, and ensuring that the protective layer 13 and the diaphragm 12 have a certain distance in the first direction X, the second direction Y, and the third direction Z, that is, by making the protective layer 13 avoid the diaphragm 12, the protective layer 13 can protect the diaphragm 12 when the MEMS composite wafer 1 is ground to reduce its thickness, thereby reducing the probability of the diaphragm 12 being damaged. This allows the MEMS composite wafer 1 to meet process requirements and improves the yield of the MEMS composite wafer 1.
[0043] Specifically, in the first direction X and the second direction Y, the distance L1 between the protective layer 13 and the groove 112 can be 1μm, 50μm, 100μm, 200μm, 400μm, 500μm or any value within the above range.
[0044] Specifically, in the third direction Z, the dimensional difference between the protective layer 13 and the diaphragm 12 can be 0.1 mm, 0.4 mm, 0.5 mm, 0.8 mm, 1 mm, or any value within the above range.
[0045] Figure 3 This is a schematic diagram of the grain structure according to one embodiment of this application. Figure 4 This is a left-side cross-sectional view of a MEMS composite die according to an embodiment of this application. Figure 2-4 As shown, in some embodiments, the groove 112 includes a first groove 1121 and a second groove 1122; the protective layer 13 has a first window 131 and a second window 132 to expose the first groove 1121 and the second groove 1122, respectively.
[0046] Each die 111 includes a first groove 1121 and a second groove 1122. A protective layer 13 is disposed between the grooves 112. That is, the protective layer 13 is not only disposed in the gaps between different dies 111, but also, for the same die 111, between the first groove 1121 and the second groove 1122. In other words, for the entire MEMS composite wafer 1, the protective layer 13 is disposed between the first grooves 1121 of different dies 111, between the second grooves 1122 of different dies 111, between the first grooves 1121 and the second grooves 1122 of different dies 111, and between the first grooves 1121 and the second grooves 1122 of the same die 111.
[0047] It should be understood that the protective layer 13 has a first window 131 and a second window 132 to expose the first groove 1121 and the second groove 1122, meaning that the first window 131 is used to expose the first groove 1121 and the second window 132 is used to expose the second groove 1122. Furthermore, as described above, the diaphragm 12 covers the groove 112 in the third direction Z, that is, it covers the first groove 1121 and the second groove 1122. Therefore, the first window 131 and the second window 132 can also be said to expose the diaphragm 12 covering the first groove 1121 and the second groove 1122.
[0048] In the above scheme, by providing a protective layer 13 on the MEMS composite wafer 1 and ensuring that the protective layer 13 avoids the diaphragm 12, the possibility of damage to the MEMS composite wafer 1 can be reduced. By providing a first window 131 and a second window 132 on the protective layer 13, so that the protective layer 13 does not cover the diaphragm 12 provided on the first groove 1121 and the second groove 1122, the diaphragm 12 can sense external pressure during the grinding process of the MEMS composite wafer 1, further improving the safety performance of the MEMS composite wafer 1.
[0049] Figure 5 This is a cross-sectional view of a MEMS composite wafer according to another embodiment of this application. Figure 6 This is a schematic diagram of the structure of a grain according to another embodiment of this application. The groove 112 includes a first groove 1121 and a second groove 1122; in the third direction Z, a protective layer 13 covers the first groove 1121 and the second groove 1122, and at least one ventilation hole 133 is provided on the protective layer 13, the at least one ventilation hole 133 being opposite to the first groove 1121 and / or the second groove 1122.
[0050] It should be understood that ventilation holes 133 are provided on the protective layer 13, meaning that the protective layer 13 does not completely cover the first groove 1121 and the second groove 1122.
[0051] It should be understood that providing at least one ventilation hole 133 on the protective layer 13 means that the number of ventilation holes 133 can be one or more. When there is one ventilation hole 133, in the third direction Z, the ventilation hole 133 can be opposite to the first groove 1121 or the second groove 1122; when there are multiple ventilation holes 133, all of the multiple ventilation holes 133 can be opposite to the first groove 1121, all of them can be opposite to the second groove 1122, or they can be opposite to both the first groove 1121 and the second groove 1122. This application does not make any special limitation on the specific number and position of the ventilation holes 133.
[0052] In the above scheme, by providing a protective layer 13 on the MEMS composite wafer 1 and ensuring that the protective layer 13 avoids the diaphragm 12, the possibility of damage to the MEMS composite wafer 1 can be reduced. In the third direction Z, when the protective layer 13 covers the first groove 1121 and the second groove 1122, by providing at least one ventilation hole 133 on the protective layer 13 and ensuring that the at least one ventilation hole 133 is opposite to the first groove 1121 and / or the second groove 1122, the diaphragm 12 can sense external pressure during the grinding process of the MEMS composite wafer 1, further improving the safety performance of the MEMS composite wafer 1.
[0053] like Figure 3 and Figure 6 As shown, in some embodiments, the die 111 further includes a pad region 114; in the third direction Z, the protective layer 13 avoids the pad region 114.
[0054] It should be understood that the solder pad area 114 here can also be referred to as PAD area 114.
[0055] In the above scheme, by setting a pad area 114 in the die 111, the pad area 114 is used as the contact position for subsequent pin bonding to ensure the normal function of MEMS composite wafer 1.
[0056] It should be noted that this application does not specifically limit the arrangement of the solder pad area 114. In the second direction Y, if the size of the solder pad area 114 is smaller than the size of the groove 112, the protective layer 13 near the solder pad area 114 can be appropriately close to the groove 112, i.e., as shown below. Figure 3 The corner 115 shown is an example. The distance L1 between the protective layer 13 and the groove 112 at the corner 115 can be appropriately reduced, which can increase the adhesion between the protective layer 13 and the MEMS wafer body 11. However, this application does not make specific limitations on whether to set the corner 115 or the size of the corner 115, but depends on the actual production process.
[0057] In some embodiments, the material of the protective layer 13 is at least one of organic materials and inorganic non-metallic materials.
[0058] Specifically, the material of the protective layer 13 can be organic materials such as polyethylene and polyvinyl chloride, or inorganic non-metallic materials such as silicon and glass.
[0059] In some embodiments, the bonding strength P between the protective layer 13 and the MEMS wafer body 11 is 0 < P ≤ 30 MPa.
[0060] In the above scheme, by making the bonding strength P between the protective layer 13 and the MEMS wafer body 11 0 < P ≤ 30 MPa, the bonding strength between the two can be ensured.
[0061] Specifically, the bonding strength P between the protective layer 13 and the MEMS wafer body 11 can be 10MPa, 15MPa, 20MPa, 25MPa, 30MPa or any value within the above range.
[0062] It should be understood that when the material of the protective layer 13 is an inorganic non-metallic material, the connection between the protective layer 13 and the MEMS wafer body 11 can also be achieved through bonding process.
[0063] In some embodiments, the material strength of the protective layer 13 is greater than or equal to 50 MPa.
[0064] In the above scheme, by making the material strength of the protective layer 13 greater than or equal to 50MPa, the protective layer 13 itself is guaranteed to have good strength, so as to avoid damage due to external force.
[0065] Figure 7 This is a partial structural schematic diagram of a MEMS composite wafer according to another embodiment of this application. Figure 7 As shown, the protective layer 13 has a positioning hole 134, which is used for positioning with the MEMS wafer body 11.
[0066] In the above scheme, positioning holes 134 are provided on the protective layer 13 to position and limit the protective layer 13 according to the shape of the MEMS wafer body 11.
[0067] In some embodiments, the protective layer 13 has visual dots, the shape of which includes at least one of a circle, a cross, or a rectangle.
[0068] In the above scheme, visual alignment and matching with the MEMS wafer body 11 can be achieved by setting visual points on the protective layer 13.
[0069] It should be understood that the purpose of setting the visual points is to further align them with the center of the MEMS wafer body 11, but this application does not impose any restrictions on the position, number, or shape of the visual points.
[0070] In addition, during the subsequent polishing process of MEMS composite wafer 1, a UV film needs to be attached to the surface, so it is also necessary to ensure good adhesion between the UV film and the protective layer 13.
[0071] This application does not limit the specific fabrication method of MEMS composite wafers. For example, they can be fabricated using the following methods: First, the MEMS wafer and the protective layer are prepared separately. Then, the protective layer is mounted on the entire MEMS wafer. This can be done in multiple steps or in a single step.
[0072] It can also be prepared by the following methods: First, adhesive is applied to the MEMS wafer, and the thickness of the adhesive coating needs to be greater than that of the separator on the MEMS. Next, a mask is prepared. After the mask is patterned (with windows or ventilation holes), it is placed on top of the adhesive. Light is irradiated through the windows or ventilation holes to modify the adhesive. The modified adhesive is then removed, thus forming a MEMS composite wafer.
[0073] Of course, the two methods mentioned above are only brief introductions. If they are the same as existing technologies or involve further structures of specific protective layers, detailed preparation can be carried out during the preparation process depending on the specific circumstances.
[0074] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.
Claims
1. A microelectromechanical system (MEMS) composite wafer, characterized in that, include: The microelectromechanical system wafer body includes a plurality of grain arrays arranged along a first direction, the grain arrays including a plurality of grains arranged along a second direction, the grains including grooves, and the first direction being perpendicular to the second direction; A diaphragm covers the groove in a third direction, the third direction being perpendicular to the first direction and the second direction; A protective layer is disposed between the grooves; in, In the first direction and the second direction, the distance L1 between the protective layer and the groove satisfies 1μm≤L1≤500μm, and there is also a distance between the protective layer and the diaphragm; In the third direction, the size of the protective layer is larger than the size of the diaphragm, and the size difference L2 satisfies 0.1mm≤L2≤1mm.
2. The composite wafer according to claim 1, characterized in that, The groove includes a first groove and a second groove; The protective layer has a first window and a second window to expose the first groove and the second groove, respectively.
3. The composite wafer according to claim 1, characterized in that, The groove includes a first groove and a second groove; In the third direction, the protective layer covers the first groove and the second groove, and the protective layer is provided with at least one ventilation hole, the at least one ventilation hole being opposite to the first groove and / or the second groove.
4. The composite wafer according to claim 1, characterized in that, The grain also includes a pad region; In the third direction, the protective layer avoids the solder pad area.
5. The composite wafer according to claim 1, characterized in that, The material of the protective layer is at least one of organic materials and inorganic non-metallic materials.
6. The composite wafer according to claim 1, characterized in that, The bonding strength P between the protective layer and the microelectromechanical system wafer body is 0 < P ≤ 30 MPa.
7. The composite wafer according to claim 1, characterized in that, The material strength of the protective layer is greater than or equal to 50 MPa.
8. The composite wafer according to any one of claims 1-7, characterized in that, The protective layer has positioning holes for positioning with the microelectromechanical system wafer body.
9. The composite wafer according to any one of claims 1-7, characterized in that, The protective layer has visual dots, the shape of which includes at least one of a circle, a cross, or a rectangle.