Die stack with controlled angle alignment

Abstract

An alignment recess formed in a cap substrate, such as a cap for a MEMS device, allows a second substrate to be bonded to the cap substrate. The alignment recess is larger than the second substrate and has two corner regions diagonally opposed to each other, with walls of the recess protruding to form a notch. The recesses are dimensioned such that the angular position of the second substrate relative to the cover substrate can be controlled within a desired amount of rotation when the second substrate is disposed within the recess and two opposing corners are surrounded by respective recesses of the recess.

Description

Technical Field

[0001] Embodiments of the subject matter described herein relate to electronic device packaging and multi-chip integration. Background Art

[0002] Semiconductor devices and other electronic devices are often assembled into packages to protect the devices from damage and provide macroscopic electrical contact. Packages can be made of various materials including polymers and ceramics. It may be necessary to assemble multiple devices in one package in order to reduce the volume required for various components in a larger assembly. It may also be necessary to interconnect multiple devices in a multi-chip package to save space and / or improve device performance characteristics such as maximum clock speed, power dissipation, etc. In applications such as motion sensing, it may be necessary to assemble multiple sensing elements in a single package. In some such applications, it is necessary to control the relative orientation of devices in a multi-device package. For example, when single-axis sensors are packaged together as a multi-axis sensor, the relative orientation needs to be controlled. Summary of the invention

[0003] In an example embodiment, a method includes forming an alignment recess in a top surface of a cover substrate, wherein a wall of the alignment recess protrudes in a first corner region to form a first recess and protrudes in a second corner region to form a second recess diagonally opposite the first recess. The alignment recess is configured to receive another substrate, the other substrate being sized such that a first corner of the other substrate rests in the first recess and a second corner of the other substrate rests in the second recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover substrate. The first and second recesses of the alignment recess are sized such that the first axis is angularly aligned with an angular spacing between an axis defined by the positions of the first and second corners of the other substrate to within less than two degrees of rotation.

[0004] Preferably, the distance between the vertex of the first recess and the vertex of the second recess is a first distance; the distance between the first corner of the second substrate and the second corner of the second substrate diagonally opposite to the first corner is a second distance; and the first distance is less than 2% greater than the second distance.

[0005] Preferably, the cover is a first cover, and the method further includes: placing a second cover patterned with a second alignment recess above the second substrate, and coupling the second cover to the first cover; and placing a third substrate in the second alignment recess and oriented along a third axis, wherein a first corner of the third substrate is placed in the first notch of the second alignment recess, and a second corner of the third substrate is placed in the second notch of the second alignment recess; wherein a wall of the second alignment recess protrudes in the first corner region to form the first notch of the second alignment recess, and protrudes in the second corner region to form the second notch of the second alignment recess diagonally opposite to the first notch of the second alignment recess; wherein the positions of the first and second notches of the second alignment recess define a third axis parallel to the top surface of the second cover; and wherein the dimensions of the third substrate and the first and second notches of the second alignment recess are set so that the angular spacing between the third axis and the fourth axis is less than two degrees of rotation.

[0006] Preferably, the method further comprises forming the alignment recess before coupling the cover to the first substrate.

[0007] Preferably, the method further comprises forming the alignment recess after coupling the cover to the first substrate.

[0008] In another embodiment, a method includes: forming an alignment recess in a top surface of a cover substrate, wherein a wall of the alignment recess protrudes in a first corner region to form a first recess and in a second corner region to form a second recess diagonally opposite to the first recess; and configuring the alignment recess to receive another substrate, the other substrate being sized such that a first corner of the other substrate rests in the first recess and a second corner of the other substrate rests in the second recess; wherein the positions of the first recess and the second recess define a first axis parallel to the top surface of the cover substrate; and wherein the first and second recesses of the alignment recess are sized such that the first axis is angularly aligned with an angular spacing between an axis defined by the positions of the first and second corners of the other substrate to within less than two degrees of rotation.

[0009] Preferably, the method further comprises: placing a second substrate as the other substrate in the alignment recess, wherein a first corner of the second substrate is placed in the first notch of the alignment recess, and a second corner of the second substrate is placed in the second notch of the alignment recess; wherein a second axis defined by the positions of the first and second corners of the second substrate is angularly aligned with the first axis to within less than two degrees of rotation.

[0010] Preferably, the distance between the vertex of the first recess and the vertex of the second recess is a first distance; the distance between the first corner of the second substrate and the second corner of the substrate diagonally opposite to the first corner is a second distance; and the first distance is less than 2% greater than the second distance.

[0011] Preferably, the method further comprises: positioning the cover substrate on the MEMS substrate above the MEMS component, and coupling the cover to the first substrate, wherein the MEMS component comprises a proof mass suspended above the MEMS substrate.

[0012] Preferably, the method further comprises: positioning the cover substrate on the MEMS substrate above the MEMS component, and coupling the cover to the first substrate, wherein the MEMS component comprises a proof mass suspended above the MEMS substrate.

[0013] In another example embodiment, a device includes an alignment recess formed in a top surface of a cover substrate, wherein a wall of the alignment recess protrudes in a first corner region to form a first recess and protrudes in a second corner region to form a second recess diagonally opposite the first recess. The alignment recess is configured to receive another substrate, the other substrate being sized such that a first corner of the other substrate rests in the first recess and a second corner of the other substrate rests in the second recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover substrate. The first and second recesses of the alignment recess are sized such that the first axis is angularly aligned to within less than two degrees of rotation with an angular spacing between a second axis defined by the positions of the first and second corners of the other substrate.

[0014] In another example embodiment, a microelectromechanical system (MEMS) device includes: a first MEMS component, the first MEMS component including a mass suspended above a first substrate and a cover coupled to the first substrate and disposed above the mass; an alignment recess, the alignment recess formed in a top surface of the cover, wherein a wall of the alignment recess protrudes in a first corner region to form a first recess and in a second corner region to form a second recess diagonally opposite the first recess, wherein the positions of the first recess and the second recess of the alignment recess define a first axis parallel to the top surface of the cover; and a second substrate, the second substrate being within the alignment recess and oriented along a second axis defined by the positions of first and second corners of the second substrate, wherein the first corner of the second substrate is disposed within the first recess of the alignment recess and the second corner of the second substrate is disposed within the second recess of the alignment recess; wherein the second substrate and the first and second recesses of the alignment recess are sized such that the angular spacing between the first axis and the second axis is less than one degree.

[0015] The distance between the apex of the first notch and the apex of the second notch is a first distance; the distance between the first corner of the second substrate and the second corner of the substrate diagonally opposite to the first corner is a second distance; and the first distance is less than 2% greater than the second distance.

[0016] The cover is a first cover, and the device further includes: a second cover patterned with a second alignment recess, the second cover is disposed above the second substrate and coupled to the first cover; and a second alignment recess, the second alignment recess is formed in the top surface of the second cover, wherein the wall of the second alignment recess protrudes in the first corner area to form a first recess, and protrudes in the second corner area to form a second recess diagonally opposite to the first recess, wherein the positions of the first recess of the second alignment recess and the second recess of the second alignment recess define a third axis parallel to the top surface of the second cover; and a third substrate, the third substrate is disposed in the second alignment recess and oriented along a fourth axis defined by the positions of the first and second corners of the second substrate, wherein the first corner of the second substrate is disposed in the first recess of the second alignment recess, and the second corner of the second substrate is disposed in the second recess of the second alignment recess; wherein the second substrate and the first and second recesses of the alignment recess are sized so that the angular spacing between the first axis and the second axis is less than two degrees of rotation.

[0017] Preferably, it also includes a second alignment recess, which is formed in the top surface of the second substrate, wherein the wall of the second alignment recess protrudes in the first corner area to form a first recess, and protrudes in the second corner area to form a second recess diagonally opposite to the first recess, wherein the positions of the first recess of the second alignment recess and the second recess of the second alignment recess define a third axis parallel to the top surface of the second substrate; and a third substrate, which is arranged in the second alignment recess and oriented along a fourth axis defined by the positions of the first and second corners of the third substrate, wherein the first corner of the third substrate is arranged in the first recess of the second alignment recess, and the second corner of the third substrate is arranged in the second recess of the second alignment recess; wherein the sizes of the first and second recesses of the second substrate and the second alignment recess are set so that the angular spacing between the first axis and the second axis is less than two degrees of rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present disclosure is illustrated by means of examples, embodiments, etc., and the present disclosure is not limited by the accompanying drawings, in which similar reference numerals indicate similar elements. The elements in the drawings are shown for simplicity and clarity, and these elements are not necessarily drawn to scale. The drawings are incorporated into and form a part of this specification together with the detailed description, and are used to further illustrate examples, embodiments, etc., and to explain various principles and advantages according to the present disclosure. In the drawings:

[0019] Figure 1 is a perspective view of an example apparatus in which embodiments disclosed herein may be practiced;

[0020] Figures 2A-2C Elements of example assemblies are shown in accordance with one or more embodiments. Figure 2A is a cross-sectional view of the component, Figure 2B is the floor plan of the component, and Figure 2C is a perspective view of the component;

[0021] Figure 3 is a diagram showing a method suitable for forming a Figures 2A-2C Process flow diagrams of cross-sectional views of steps in example processes of components and similar devices;

[0022] Figures 4A-4C Another example assembly is shown in accordance with one or more embodiments. Figure 4A is a cross-sectional view of the component, Figure 4B is a top plan view of a cover portion assembly, and Figure 4C is a bottom plan view of the die prior to being bonded to a cover cap;

[0023] Figures 5A-5C Elements of another example assembly are shown in accordance with one or more embodiments. Figure 5A is a cross-sectional view of the component, Figure 5B is a plan view of the cover portion of the assembly, and Figure 5C is a perspective view of the component;

[0024] Figure 6 is a diagram showing a method suitable for forming a Figures 5A-5C Process flow diagrams of cross-sectional views of steps in an example process of assemblies of the invention and similar assemblies; and

[0025] Figure 7A-7B Features of another cover according to one or more embodiments are shown. Fig. 7A is a cross-sectional view, and Figure 7B It is a perspective drawing. DETAILED DESCRIPTION

[0026] The following detailed description provides examples for the purpose of understanding and is not intended to limit the invention or the application and use of the invention. In addition, it is not intended to be bound by any explicit or implicit theory presented in the foregoing technical field, background technology or the following detailed description.

[0027] For simplicity and clarity of illustration, the drawings illustrate general constructions, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present invention. In addition, the elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements or regions in the drawings may be enlarged relative to other elements or regions to help improve understanding of embodiments of the present invention.

[0028] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims may be used to distinguish similar elements and are not necessarily used to describe a specific sequential order or time order. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the invention described herein are, for example, capable of operating in a sequence other than that shown or otherwise described herein. In addition, the terms "comprise", "include", "have" and any variations thereof are intended to cover non-exclusive inclusions, so that a process, method, article or device including a series of elements is not necessarily limited to those elements, but may include other elements that are not explicitly listed or inherent to such processes, methods, articles or devices. The term "coupled" as used herein is defined as being connected directly or indirectly in an electrical or non-electrical manner. As used herein, the terms "substantially" and "substantially" mean sufficient to achieve the stated purpose in a practical manner, and minor defects (if any) are not important for the stated purpose.

[0029] Unless otherwise stated, directional references such as "top", "bottom", "left", "right", "above", "below", etc. are not intended to require any preferred orientation, but are made for illustration purposes with reference to the orientation of the corresponding figure or figures.

[0030] It should be understood that the steps of the various processes described herein are non-limiting examples of suitable processes according to embodiments and are used for illustration purposes. Systems and devices according to embodiments herein may use any suitable process, including processes that omit steps described herein, perform those steps in a different order, and similar steps, etc. It should also be understood that well-known features may be omitted for clarity.

[0031] Figure 1 An example device in which embodiments of the present disclosure may be practiced is shown. Device 100 includes a lead frame 102, a carrier substrate 104, and devices 110, 130, 150 in a stacked arrangement. In this example, wire bonding connections are made from devices 110, 130, 150 to carrier substrate 104 and from carrier substrate 104 to lead frame 102. Device 100 may be configured to be used as a multi-axis motion sensor. For example, device 110 may be an x-axis motion sensor, device 130 may be a y-axis motion sensor, and device 150 may be a z-axis motion sensor. In this example, it is desirable that the x-axis, y-axis, and z-axis are all orthogonal to each other (or as close to orthogonal as possible to ensure the accuracy of device 100). However, when devices 110, 130, 150 are assembled together to form device 100, misalignment of these devices may occur. In some previous methods, alignment accuracy is limited by the accuracy of the automated assembly system. Therefore, embodiments herein provide devices and methods that include mechanical features that allow for improved alignment of one device relative to another using conventional assembly equipment.

[0032] Figures 2A-2C Elements of example assemblies are shown in accordance with one or more embodiments. Figure 2A is a cross-sectional view; Figure 2B is a plan view from above; and Figure 2C2 is a perspective view. Assembly 200 includes a device 210 coupled to a die 230. In this non-limiting example, device 210 is a micro-electromechanical system (MEMS) device, such as an accelerometer, that includes a proof mass 214 suspended above a substrate 212. A cover 220 is bonded to substrate 212 via a spacer 215 to protect proof mass 214. Cover 220 has an alignment recess (i.e., recess 222) that is configured to receive die 230 and includes features that can be used to control rotational alignment of die 230 relative to cover 220 and device 210, as further described below. The cross-sectional view of assembly 200 corresponds to a line that perpendicularly bisects a plan view of a top surface 221 of cover 220. The dashed area within recess 222 corresponds to the location of a protrusion in the wall of recess 222 that forms a notch in corner regions 224a, 224b.

[0033] As can be more clearly understood from the plan and perspective views of the cover 220, the recess 222 has a larger footprint than the die 230 and has four corner regions 224 along the outer wall of the recess 222. The wall of the recess 222 protrudes toward the center of the recess 222 in two of the corner regions 224 that are diagonally opposite each other (corner regions 224a, 224b). Each of the corner regions 224a, 224b has a notch that is sized and positioned so that when the die 230 is approximately centered in the recess 222, the notch surrounds the corresponding corner of the die 230. Therefore, the rotation of the die 230 within the recess 222 is limited by the angle 299 between the axis 290 that passes through the vertex of each notch at the corner regions 224a,b and the axis 295 that passes through the corresponding corner of the die 230 as shown schematically. The walls of the recess 222 surrounding each notch need not be stepped. For example, the walls of the recess 222 may alternatively be rounded, as indicated by the dashed lines in the corner region 224a, or may have any other suitable shape. Figure 2B In the plan view of FIG. 2 , the relative footprint of the die 230 is exaggerated for illustration. It should be understood that any suitable axis may be used to define the angular offset between the orientation of the device (e.g., the die 230) and its desired angular orientation, and Figure 2B Axes 290, 295 are for illustration purposes only.

[0034] A recess (e.g., recess 222) according to one or more embodiments herein can be sized to achieve a desired degree of control over the angular orientation of a substrate, die, or other device (e.g., die 230). For example, it will be appreciated that when the width of a recess is measured diagonally from the vertex of one recess to the opposite recess (e.g., from the vertex of the recess at corner region 224a to the vertex of the recess at corner region 224b), it is only slightly greater than the diagonal width of the die positioned within the recess (e.g., from the vertex of the recess at corner region 224a to the vertex of the recess at corner region 224b). Figures 2A-2C), the angular range of motion of the die will be relatively small. At the same time, if the recess is enlarged relative to the die, the angular range of motion of the die will become larger.

[0035] The size of the recess relative to the substrate to be placed in the recess can be selected to accommodate the alignment capabilities of any tool or process used to place the substrate in the recess. For example, in one or more embodiments, a recess such as recess 222 and a die such as die 230 are configured together to control the angular position of the device within two degrees of rotation, while in some such embodiments, the angular position is controlled within one degree of rotation, and in other such embodiments, the angular position is controlled within a predetermined limit between one degree of rotation and two degrees of rotation, which can also depend on the capabilities of the die placement equipment employed by the user. In one or more embodiments, when the die is placed in the recess, the distance from the vertex of one recess to the second recess (e.g., from the vertex of the recess at corner region 224a to the vertex of the recess at corner region 224b) is less than 2% greater than the distance between the corresponding corners of the die. It should be understood that the relative size of the recess and the die can vary based on the absolute size of the die. The recess size according to the embodiments herein can be set to accommodate a typical device die. By way of example, as a non-limiting example, the recess may have a depth in the range of 50-100 μm.

[0036] Figure 3 Describe suitable for forming Figures 2A-2C The process 300 includes steps 310, 320, 330, 340, 350, and 360 described below with reference to the components of the assembly 200. It should be understood that in one or more embodiments, steps of the process 300 or similar steps may be omitted or replaced with steps described in conjunction with the present invention. Figure 3 The steps may be performed in any suitable order other than the order described.

[0037] At step 310, the device 210 (i.e., substrate 212 with proof mass 214 suspended above substrate 212) is received. At step 320, a spacer 215 is formed on substrate 212 adjacent to and above proof mass 214. The spacer may be any suitable material. For example, in one or more embodiments, the spacer 215 is a glass frit, while in one or more other embodiments, the spacer 215 is a metallic material, such as aluminum or germanium, that may form an alloy that bonds the cover 220 to the substrate 212. In one or more other embodiments, the spacer 215 may be an adhesive or other curable polymer precursor. It should be understood that in one or more alternative processes, the spacer 215 may be a pre-existing feature on the substrate 212 to which the cover 220 is bonded by any suitable method, including but not limited to known wafer bonding methods.

[0038] At step 330, the cover 220 is bonded to the substrate 212 via the spacer 215. The cover, such as the cover 220, can be formed of any suitable material. In one or more embodiments, the cover 220 is formed of a semiconductor substrate including silicon (Si), silicon germanium (SiGe), gallium nitride (GaN), gallium arsenide (GaAs), silicon carbide (SiC), etc. In one or more embodiments, the cover, such as the cover 220, is formed of silicon oxide (e.g., glass or quartz), silicon nitride, aluminum oxide, etc.

[0039] At step 340, a recess 222 is formed in the cover 220, including Figures 2A-2C 224a, 224b shown in FIG. The recesses 222 may be formed by any suitable process, including but not limited to a photolithography process, in which a masking material (e.g., photoresist) is patterned over the cover cap 220, and the cover cap 220 is selectively etched using wet chemical etching, plasma etching, or any other suitable process to form the recesses 222 in the areas not protected by the masking material. In one or more embodiments, the cover cap 220 may be directly patterned via a micromachining process such as laser ablation.

[0040] At step 350, the die 230 is placed in the recess 222 and coupled to the cover 220 via any suitable method, including but not limited to bonding the die 230 to the cover 220 using an adhesive film, a curable polymer, solder, or other material (not shown). At step 360, the assembly 200 is fully formed with the die 230 secured to the cover 220 within the recess 222.

[0041] In one or more embodiments, recesses such as recess 222 are patterned in a cover such as cover 220 before it is joined to a substrate such as substrate 212 (ie, step 340 may be performed before step 330).

[0042] Figures 4A-4C Another example assembly is shown in accordance with one or more embodiments. Figure 4A is a cross-sectional view of the component; Figure 4B is a top plan view of the cover portion; and Figure 4C4 is a bottom plan view of a die prior to being bonded to a cover cap. Similar to assembly 200, assembly 400 includes an apparatus 410 that includes a substrate 412 and a proof mass 414 suspended above substrate 412. Cover cap 420 is coupled to substrate 412 via a spacer 415 (e.g., spacer 215) disposed adjacent to and above proof mass 414. Die 430 is disposed within a recess 422 in cover cap 420 and is coupled to cover cap 420 via a die attach material 432. The cross-sectional view of assembly 400 corresponds to a line of the plan view that perpendicularly bisects a top surface 421 of cover cap 420. The dashed area within recess 422 corresponds to the location of a protrusion in the wall of recess 422 that forms a chamfered surface at a corner area 424, as described below. The recess 422 is configured to ensure that the bottom surface 431 of the die 430 remains as coplanar as possible with the top surface 421 of the cover 420 after being bonded to the cover 420, which can be referred to as Figures 4A-4C This can be understood from the plan view of the cover 420 and the die 430 in FIG.

[0043] As shown, in a plan view of the cover 420, one suitable arrangement of the recess 422 is a rectangular shape with chamfers at the corner regions 424 (i.e., an octagonal recess). It should be understood that the protruding area of ​​the wall of the recess 422 in the corner regions 424 may have any suitable geometry (e.g., the chamfered portion shown may alternatively be circular). The recess 422 has a footprint that is smaller than the footprint of the die 430 indicated by the dashed line surrounding the recess 422. The die 430 has a die attach material 432 disposed on the bottom of the die 430, the die attach material 432 being patterned to have a shape complementary to the recess 422. The footprint of the die attach material 432 on the die 430 is also smaller than the footprint of the recess 422. When the die 430 is in contact with the cover 420, all or a portion of each corner 434 rests on the top surface 421 of the cover 420 over the recess 422 (i.e., over the corner region 424). The die attach material 432 is configured to deform when the die 430 is bonded to the cover 420 using any suitable process. The die attach material is patterned so that the material can flow or deform laterally to further fill the recess 422 while remaining contained within the recess 422 without displacing the die 430 from resting directly on the cover 420 over the recess. Thus, when the die 430 is placed directly above the recess 422, the bottom surface 431 of the die 430 will be aligned with the top surface of the cover 420 to within the limits of the flatness of the top surface 421 of the cover 420 and the bottom surface 431 of the die 430 (e.g., the rotation 499 between the axis 490 parallel to the top surface 421 of the cover and the axis 495 parallel to the bottom surface 431 of the die 430 will be less than a predetermined amount).

[0044] It should be appreciated that assembly 400 is described for purposes of illustration and that other arrangements are possible. For example, in one or more embodiments, a die attach material such as die attach material 432 may be disposed within a recess such as recess 422 rather than on a die such as die 430 prior to completing an assembly such as assembly 400.

[0045] In one or more embodiments, the die attach material, such as die attach material 432, is a die attach film or other adhesive material (e.g., a silicone adhesive) that can flow or deform under pressure when contacting a recess of a cover (e.g., recess 422 of cover 420) and / or a bottom surface of a die (e.g., die 430). In one or more other embodiments, such a die attach material is a solder or a sinter that is heated to bond the die to the cover. In one or more other embodiments, the die attach material, such as die attach material 432, is a polymeric material, such as an epoxy compound, including but not limited to a conductive epoxy such as a silver epoxy.

[0046] Figures 5A-5C Elements of example assemblies are shown in accordance with one or more embodiments. Figure 5A is a cross-sectional view of the component; Figure 5B is a top plan view of the cover portion of the assembly; and Figure 5C 5 is a perspective view. Assembly 500 includes a device 510 coupled to a die 530. In this non-limiting example, device 510 is a micro-electromechanical system (MEMS) device, such as an accelerometer, that includes a proof mass 514 suspended above a substrate 512. A cover 520 is bonded to substrate 512 (e.g., substrate 212 / 412) via a spacer 515 (e.g., spacer 215 / 415) to protect proof mass 514. Cover 520 has an alignment recess (i.e., recess 522) configured to receive die 530. Recess 522 includes features that are further described below that can be used to control both the rotational alignment of die 530 relative to cover 520 (and device 510), and features that ensure that die 530 will be coplanar with a top surface 521 of cover 520 within the limits of the planarity of the surface of cover 520 and the bottom surface of die 530. The cross-sectional view of assembly 500 corresponds to a line that perpendicularly bisects a plan view of top surface 521 of cover 520. The dashed areas within the cross-section of recess 522 correspond to the locations of protrusions in the walls of recess 522 that form notches and platform areas in corner area 524a and platform areas in corner area 524c.

[0047] As can be seen in a plan view of the top surface 521 of the cover 520, the recess 522 has corner areas 524a, 524b diagonally opposite to each other and corner areas 524c, 524d opposite to each other. All four corners 524 include a first depth (see Figure 5A The platform area of ​​the depth D1 in the cross-sectional view of FIG. 5 is less than the depth of the recess 522 outside the corner area 524. The coverage area of ​​these areas is Figure 5B These platform areas function similarly to Figures 4A-4C The corner regions 424 of the recess 422 are formed in a rectangular shape and allow the die 530 to be supported above the bottom of the recess 522 at its corners.

[0048] In two of the corner regions 524 (corner regions 524a, 524b), the outer edge of the recess 522 protrudes toward the center of the recess 522. Each of the corner regions 524a, 524b has a notch sized and positioned so that when the die 530 is approximately centered in the recess 522, the notch surrounds the corresponding corner of the die 530. The notches in the corner regions 524a, 524b function similarly to Figures 2A-2C Specifically, when the recess 522 and the tube core 530 are appropriately sized, the angular orientation of the tube core 530 can be controlled within a desired range.

[0049] At step 610, cover 520 is received. Cover 520 may be received as a separate part, or may already be joined to substrate 512 of device 510. At step 620, portions of recess 522 outside the platform area of ​​corner region 524 (i.e., portions of the recess having a Figure 5A 520 is a portion of the depth D2 shown in FIG. 520 . Recess 522 may be formed by any suitable process, including but not limited to a photolithography process, in which a masking material (e.g., photoresist) is patterned over cover cap 520, and cover cap 520 is selectively etched (e.g., using wet chemical etching or plasma etching) to form recess 522 in areas not protected by the masking material. In one or more embodiments, a cover cap such as cover cap 520 may be directly patterned via a micromachining process such as laser ablation to form a recess such as recess 522.

[0050] At step 630, the cover 520 is further patterned using any suitable process to form a terrace region in the corner 524 of the recess 522 (ie, a portion of the recess 522 having a shape such as Figure 5A The formation of the terrace region in the corner regions 524a, 524b also causes a notch to be formed in the corner regions 524a, 524b.

[0051] At step 640, the die 530 (shown with die attach material 532 on bottom surface 531) is contacted with the cover 520 and disposed within the recess 522. Pressure or heat may be applied to deform the die attach material 532, spreading away from the center of the die 530 toward the edge of the recess 522.

[0052] Finally, at step 650, the die 530 is placed in the recess 522, with the corners 534 of the die 530 resting on the landing areas at the corners 524 of the recess 522. The die 530 is bonded to the cover lid 520 by the die attach material 532.

[0053] It should be understood that in one or more embodiments, a die attach material such as die attach material 532 (e.g., die attach material 432) may be placed in a recess of a cover (e.g., recess 522 of cover 520) before bonding the die to the cover, rather than placing the die attach material on the die. It should also be understood that any suitable materials and processes may be used to bond the die to the cover according to embodiments herein. Thus, in one or more embodiments, a die attach material such as die attach material 532 is a die attach film or other adhesive material (e.g., a silicone adhesive) that may flow or deform under pressure when contacting the recess (e.g., recess 522) and / or contacting the bottom surface of the die (e.g., die 530). In one or more other embodiments, such a die attach material is a solder or sinter that is heated to bond the die to the cover. In one or more other embodiments, the die attach material, such as the die attach material 532 , is an epoxy compound, including but not limited to a conductive epoxy, such as a silver-containing epoxy.

[0054] Fig. 7A are cross-sectional and perspective views of cover 720 according to one or more embodiments, and Figure 7B 7 is a perspective view of cover 720. Cover 720 includes features that enable a die to be bonded to cover 720 in a manner that allows both rotational alignment and tilt of the die to be controlled relative to the orientation of cover 720. Figure 7A-7BIn the example of , the cover 720 is provided with a set of raised features on its top surface 721, which are similar in function to the features of the corner 524 of the cover 520. However, the cover 720 does not require a recess such as the recess 522. Features 724a, 724b are positioned diagonally opposite each other similarly to the corner areas 524a, 524b of the cover 520. Each of the features 724a, 724b has a platform area extending to a height H1 indicated in the cross-sectional view surrounded by a notched sidewall, which extends above the top surface 721 to a height H2 indicated in the cross-sectional view. The platform area of ​​features 724c, 724d also extends to a height H1, and is positioned diagonally opposite each other similarly to the corner areas 524c, 524d of the cover 520, and serves as an additional platform area for a die such as the die 530.

[0055] example

[0056] Features of the embodiments may be understood with the aid of one or more of the following examples:

[0057] Example 1: A method or apparatus includes a cover that is disposed on a first substrate above a first microelectromechanical system (MEMS) component and coupled to the first substrate. An alignment recess is formed in a top surface of the cover, and a wall of the alignment recess protrudes in a first corner region to form a first recess, and protrudes in a second corner region to form a second recess diagonally opposite the first recess. This example also includes a second substrate that is disposed in the alignment recess and oriented along a second axis, wherein a first corner of the second substrate is disposed in the first recess of the alignment recess, and a second corner of the second substrate is disposed in the second recess of the alignment recess. The positions of the first and second recesses of the alignment recess define a first axis parallel to the top surface of the cover. The second substrate and the first and second recesses of the alignment recess are sized such that the angular spacing between the first axis and the second axis is less than a predefined rotation amount.

[0058] Example 2: The method or apparatus of example 1, wherein the second substrate and the first and second recesses of the alignment recess are sized such that the angular spacing between the first axis and the second axis is between one degree of rotation and two degrees of rotation.

[0059] Example 3: The method or apparatus of example 1, wherein the second substrate and the first and second recesses of the alignment recess are sized such that the angular separation between the first axis and the second axis is less than one degree of rotation.

[0060] Example 4: A method or device according to any one of Examples 1-3, wherein the distance between the vertex of the first recess and the vertex of the second recess is a first distance; wherein the distance between the first corner of the second substrate and the second corner of the second substrate diagonally opposite to the first corner is a second distance; and wherein the first distance is less than a predetermined amount than the second distance.

[0061] Example 5: A method or apparatus according to Example 4, wherein the first distance is less than 2% greater than the second distance.

[0062] Example 6: A method or apparatus according to Example 4, wherein the first distance is 1% to 2% greater than the second distance.

[0063] Example 7: The method or apparatus of any of Examples 1-6, wherein the cover is a first cover and further comprises: a second cover patterned with a second alignment recess, the second cover disposed over the second substrate, and the second cover coupled to the first cover.

[0064] Example 8: The method or apparatus according to Example 7 further includes a third substrate disposed in the second alignment recess and oriented along a third axis. The first corner of the third substrate is disposed in the first notch of the second alignment recess, and the second corner of the third substrate is disposed in the second notch of the second alignment recess. The wall of the second alignment recess protrudes in the first corner region of the second alignment recess to form the first notch of the second alignment recess, and protrudes in the second corner region of the second alignment recess to form the second notch of the second alignment recess diagonally opposite to the first notch of the second alignment recess. The positions of the first and second notches define a third axis parallel to the top surface of the second cover. The dimensions of the third substrate and the first and second notches of the second alignment recess are set so that the angular spacing between the third axis and the fourth axis is less than two degrees of rotation.

[0065] Example 9: The method or apparatus of Example 7, wherein the alignment recess is formed prior to coupling the cover to the first substrate.

[0066] Example 10: The method or apparatus of Example 7, wherein the alignment recess is formed after coupling the cover to the first substrate.

[0067] Example 11: The method or apparatus of Example 7, further comprising a cover substrate disposed on the MEMS substrate over the MEMS component and coupled to the first substrate.

[0068] Example 12: The method or apparatus of any of Examples 1-11, wherein the MEMS component comprises a proof mass suspended above a MEMS substrate.

[0069] Example 13: A method or apparatus comprising an alignment recess formed in a top surface of a cover substrate, wherein a wall of the alignment recess protrudes in a first corner region to form a first recess and protrudes in a second corner region to form a second recess diagonally opposite the first recess. The alignment recess is configured to receive another substrate, the other substrate being sized such that a first corner of the other substrate rests in the first recess and a second corner of the other substrate rests in the second recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover substrate. The first and second recesses of the alignment recess are sized such that the first axis is angularly aligned with an angular spacing between an axis defined by the positions of the first and second corners of the other substrate to within less than two degrees of rotation.

[0070] Example 14: The method or apparatus of Example 13, wherein the second substrate and the first and second recesses of the alignment recess are sized such that the angular spacing between the first axis and the second axis is between one degree of rotation and two degrees of rotation.

[0071] Example 15: The method or apparatus of Example 13, wherein the second substrate and the first and second recesses of the alignment recess are sized such that the angular separation between the first axis and the second axis is less than one degree of rotation.

[0072] Example 16: The method or apparatus of any one of Examples 13-15, comprising a second substrate disposed in the alignment recess as the other substrate. A first corner of the second substrate is disposed in a first notch of the alignment recess, and a second corner of the second substrate is disposed in a second notch of the alignment recess. A second axis is defined by the positions of the first and second corners of the second substrate, angularly aligned with the first axis to within less than two degrees of rotation.

[0073] Example 17: A method or device according to Example 16, wherein the distance between the vertex of the first recess and the vertex of the second recess is a first distance; wherein the distance between the first corner of the second substrate and the second corner of the substrate diagonally opposite to the first corner is a second distance; and wherein the first distance is less than 2% greater than the second distance.

[0074] The foregoing detailed description and examples are merely illustrative in nature and are not intended to limit the embodiments of the subject matter or the application and use of such embodiments. As used herein, the word "exemplary" means "serving as an example, instance, or illustration". Any embodiment described herein as exemplary should not necessarily be construed as being preferred or advantageous over other embodiments. In addition, it is not intended to be bound by any explicit or implicit theory presented in the foregoing technical field, background technology, or specific embodiments.

[0075] It should be understood that the application of the present invention is not limited to the details of the construction and arrangement of the components set forth in the foregoing description or shown in the accompanying drawings. The present invention can have other embodiments and can be practiced or carried out in various ways. Moreover, it should be understood that the words and terms used herein are for illustrative purposes and should not be considered as restrictive. The use of "including" and "comprising" or "having" and their variations herein is intended to cover the items listed thereafter and their equivalents and additional items. Unless otherwise specified or limited, the terms "mount", "connect", "support" and "couple" and their variations are widely used and cover direct and indirect mounting, connection, support and coupling. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings.

[0076] The foregoing discussion is presented to enable those skilled in the art to implement and use embodiments of the present invention. Without departing from embodiments of the present invention, those skilled in the art will readily appreciate various modifications to the illustrated embodiments, and the principles herein may be applied to other embodiments and applications. Therefore, embodiments of the present invention are not intended to be limited to the illustrated embodiments, but should be given the widest scope consistent with the principles and features disclosed herein. The foregoing detailed description should be read with reference to the figures, in which similar elements in different figures have similar reference numerals. The figures, which are not necessarily drawn to scale, depict selected embodiments, and are not intended to limit the scope of embodiments of the present invention. Those skilled in the art will recognize that the examples provided herein have many useful alternatives and are within the scope of embodiments of the present invention.

[0077] The connecting lines shown in the various figures included herein are intended to represent exemplary functional relationships and / or physical couplings between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in one or more embodiments of the subject matter. In addition, certain terms may also be used herein only for reference purposes, and therefore the terms are not intended to be restrictive, and unless the context clearly indicates, the terms "first", "second" and other such numerical terms referring to structures do not imply order or sequence.

[0078] The foregoing description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless otherwise expressly stated, "connected" means that one element is directly joined to another element (or is directly communicated with another element), and not necessarily mechanically joined. Likewise, unless otherwise expressly stated, "coupled" means that one element is directly or indirectly joined to another element (or is directly or indirectly communicated with another element electrically or otherwise), and not necessarily mechanically joined. Thus, although the schematic diagrams shown in the drawings depict an exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in one or more embodiments of the depicted subject matter.

Claims

1. A method, characterized in that include: disposing a cover on a first substrate over a first microelectromechanical system (MEMS) component and coupling the cover to the first substrate, wherein the MEMS component includes a proof mass suspended above the first substrate; forming an alignment recess in a top surface of the cover, wherein a wall of the alignment recess protrudes in a first corner region to form a first notch and protrudes in a second corner region to form a second notch diagonally opposite the first notch; as well as disposing a second substrate within the alignment recess and oriented along a second axis, wherein a first corner of the second substrate is disposed within the first notch of the alignment recess and a second corner of the second substrate is disposed within the second notch of the alignment recess; wherein the positions of the first and second recesses of the alignment recess define a first axis parallel to the top surface of the cover; and The second substrate and the first and second recesses of the alignment recess are sized such that an angular separation between the first axis and the second axis is less than two degrees.

2. The method according to claim 1, characterized in that The distance between the vertex of the first notch and the vertex of the second notch is a first distance; A distance between a first corner of the second substrate and a second corner of the second substrate diagonally opposite to the first corner is a second distance; and The first distance is less than 2% greater than the second distance.

3. The method according to claim 1, characterized in that The cover is a first cover, and the method further comprises: disposing a second cover cap patterned with second alignment recesses over the second substrate and coupling the second cover cap to the first cover cap; and disposing a third substrate within the second alignment recess and oriented along a third axis, wherein a first corner of the third substrate is disposed within the first notch of the second alignment recess and a second corner of the third substrate is disposed within the second notch of the second alignment recess; wherein a wall of the second alignment recess protrudes in a first corner region to form the first notch of the second alignment recess, and protrudes in a second corner region to form the second notch of the second alignment recess diagonally opposite the first notch of the second alignment recess; wherein the positions of the first and second recesses of the second alignment recess define a third axis parallel to the top surface of the second cover; and The third substrate and the first and second recesses of the second alignment recess are sized such that an angular separation between the third axis and the fourth axis is less than two degrees of rotation.

4. The method according to claim 1, characterized in that The method additionally includes forming the alignment recess before or after coupling the cover to the first substrate.

5. A method, characterized in that include: forming an alignment recess in a top surface of the cover substrate, wherein a wall of the alignment recess protrudes in a first corner region to form a first notch and protrudes in a second corner region to form a second notch diagonally opposite the first notch; as well as configuring the alignment recess to receive another substrate, the other substrate being sized such that a first corner of the other substrate rests in the first recess and a second corner of the other substrate rests in the second recess; wherein the positions of the first recess and the second recess define a first axis parallel to the top surface of the cover substrate; and Wherein the first and second recesses of the alignment recess are sized such that the first axis is angularly aligned to within less than two degrees of rotation with an angular spacing between an axis defined by the positions of the first and second corners of the other substrate.

6. The method according to claim 1, characterized in that Also includes: The cap substrate is disposed on a MEMS substrate over a MEMS component and the cap is coupled to the first substrate, wherein the MEMS component includes a proof mass suspended over the MEMS substrate.

7. A micro-electromechanical system (MEMS) device, characterized in that: include: a first MEMS component including a proof-mass suspended above a first substrate and a cover coupled to the first substrate and disposed above the proof-mass; an alignment recess formed in a top surface of the cover, wherein a wall of the alignment recess protrudes in a first corner region to form a first notch and protrudes in a second corner region to form a second notch diagonally opposite the first notch, wherein the positions of the first notch of the alignment recess and the second notch of the alignment recess define a first axis parallel to the top surface of the cover; as well as a second substrate within the alignment recess and oriented along a second axis defined by the positions of first and second corners of the second substrate, wherein the first corner of the second substrate is disposed within the first notch of the alignment recess and the second corner of the second substrate is disposed within the second notch of the alignment recess; The second substrate and the first and second recesses of the alignment recess are sized such that an angular separation between the first axis and the second axis is less than one degree.

8. The device according to claim 7, characterized in that The distance between the vertex of the first notch and the vertex of the second notch is a first distance; A distance between a first corner of the second substrate and a second corner of the substrate diagonally opposite to the first corner is a second distance; and The first distance is less than 2% greater than the second distance.

9. The device according to claim 7, characterized in that The cover is a first cover, and the device further comprises: a second cover cap patterned with second alignment recesses, the second cover cap disposed over the second substrate and coupled to the first cover cap; and a second alignment recess formed in the top surface of the second cover, wherein a wall of the second alignment recess protrudes in a first corner region to form a first notch and protrudes in a second corner region to form a second notch diagonally opposite to the first notch, wherein the positions of the first notch of the second alignment recess and the second notch of the second alignment recess define a third axis parallel to the top surface of the second cover; and a third substrate disposed within the second alignment recess and oriented along a fourth axis defined by the positions of first and second corners of the second substrate, wherein the first corner of the second substrate is disposed within the first notch of the second alignment recess and the second corner of the second substrate is disposed within the second notch of the second alignment recess; The second substrate and the first and second recesses of the alignment recess are sized such that an angular separation between the first axis and the second axis is less than two degrees of rotation.

10. The device according to claim 7, characterized in that Also includes: a second alignment recess formed in the top surface of the second substrate, wherein a wall of the second alignment recess protrudes in a first corner region to form a first notch and protrudes in a second corner region to form a second notch diagonally opposite to the first notch, wherein positions of the first notch of the second alignment recess and the second notch of the second alignment recess define a third axis parallel to the top surface of the second substrate; as well as a third substrate disposed within the second alignment recess and oriented along a fourth axis defined by the positions of first and second corners of the third substrate, wherein the first corner of the third substrate is disposed within the first notch of the second alignment recess and the second corner of the third substrate is disposed within the second notch of the second alignment recess; The second substrate and the first and second recesses of the second alignment recess are sized such that an angular separation between the first axis and the second axis is less than two degrees of rotation.

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