Die stack with controlled slift and angle alignment

Abstract

An alignment feature formed on a cap substrate allows a second substrate to be bonded to the cap substrate while ensuring that the second substrate is not tilted relative to a plane defined by the alignment feature. The die attach material is patterned such that it deforms or flows below the second substrate while allowing corners of the second substrate to rest on a platform region elevated above a top surface of the cap substrate. Some of the plateau regions may include additional features that are raised above the plateau regions to form notches that constrain the rotational position of the second substrate in addition to constrain the slope of the second substrate.

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 to provide macroscopic electrical contact. Packages can be made of a variety of materials, including polymers and ceramics. It may be desirable to assemble multiple devices in a package to reduce the volume required for the individual components in a larger assembly. It may also be desirable to interconnect multiple devices in a multi-chip package to save space and / or improve device performance characteristics, such as maximum clock speed, power consumption, etc. In applications such as motion sensing, it may be desirable to assemble multiple sensing elements in a single package. In some such applications, it is desirable 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, it is desirable to control the relative orientation. Summary of the invention

[0003] In an example embodiment, a method includes placing a cover over a first substrate and coupling to the first substrate. An alignment recess is formed in a top surface of the cover, wherein the alignment recess has a first length and a first width at a center of the alignment recess; and wherein the alignment recess has a second length less than the first length and a second width less than the first width at each of four corner regions of the alignment recess. A second substrate is placed over the alignment recess on the top surface of the cover. The second substrate has a third length greater than the second length and a third width greater than the second length. A die attach material is made to fill a portion of the alignment recess so that the corners of the second substrate rest on a surface of the cover around the alignment recess, and the second substrate is bonded to the cover through the die attach material within the alignment recess. In one or more embodiments, the first substrate belongs to a first MEMS component, and the first MEMS component includes a block suspended above the first substrate.

[0004] In one or more embodiments, the method further includes: placing a certain volume of the tube core attachment material in the alignment recess, which is configured to deform or flow during the bonding process of bonding the second substrate to the cover lid; wherein the volume of the tube core attachment material is less than the total volume of the alignment recess. In one or more embodiments, the bonding process is a thermocompression bonding process or a solder reflow process. In one or more embodiments, the method further includes: patterning a certain volume of the tube core attachment material on the back surface of the second substrate, which is configured to deform or flow during the bonding process of bonding the second substrate to the cover lid; wherein the tube core attachment material is not present in the back surface of the second substrate at the corners of the second substrate. In one or more embodiments, the method further includes forming the alignment recess before coupling the cover lid to the first substrate. In one or more embodiments, the method further includes forming the alignment recess after coupling the cover lid to the first substrate.

[0005] In one or more embodiments, the method also includes: forming a second alignment recess in the top surface of the second substrate, wherein the second alignment recess has a fourth length and a fourth width at the center of the second alignment recess; and wherein the alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of the four corner regions of the second alignment recess; placing a third substrate on the top surface of the second substrate above the second alignment recess, the second substrate having a sixth length greater than the fifth length and having a sixth width greater than the fifth length; and filling a portion of the second alignment recess with a die attach material so that the corners of the third substrate rest on the surface of the second substrate, surrounding the alignment recess, and the third substrate is bonded to the second substrate through the die attach material within the second alignment recess.

[0006] In one or more embodiments, the method also includes: placing a second cover over the second substrate; forming a second alignment recess in the top surface of the second cover, wherein the second alignment recess has a fourth length and a fourth width at the center of the second alignment recess; and wherein the alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of the four corner regions of the second alignment recess; placing a third substrate on the top surface of the second cover over the second alignment recess, the third substrate having a sixth length greater than the fifth length and a sixth width greater than the fifth length; and filling a portion of the second alignment recess with a die attach material so that the corners of the third substrate rest on the top surface of the second cover, surrounding the second alignment recess, and the third substrate is bonded to the second cover via the die attach material within the second alignment recess.

[0007] In an example embodiment, a device includes a cover cap disposed above a first substrate and coupled to the first substrate. The device also includes an alignment recess formed in a top surface of the cover cap, wherein the alignment recess has a first length and a first width at a center of the alignment recess. The alignment recess has a second length less than the first length and a second width less than the first width at each of four corner regions of the alignment recess. A second substrate is disposed above the alignment recess on the top surface of the cover cap. The second substrate has a third length greater than the second length and a third width greater than the second length. A die attach material fills a portion of the alignment recess so that the corners of the second substrate rest on a surface of the cover cap surrounding the alignment recess. The second substrate is bonded to the cover cap by the die attach material in the alignment recess. In one or more embodiments, the first substrate belongs to a first MEMS component, and the first MEMS component includes a block suspended above the first substrate.

[0008] In another example embodiment, a method includes placing a cover over a first substrate and coupling the cover to a first substrate; forming an alignment region on a top surface of the cover. The alignment region includes platform surfaces at four corners of the alignment region, the platform surfaces extending to a first height above the top surface of the cover within the alignment region. The alignment region also includes: a first raised recess partially surrounding the first platform surface at a first corner of the alignment region and extending above the first platform surface; and a second raised recess partially surrounding the second platform surface at a second corner of the alignment region diagonally opposite to the first corner and extending above the second platform surface. A second substrate is placed in the alignment region so that the corners of the second substrate rest on corresponding platform areas in the alignment region, wherein the first corner of the second substrate rests in the first raised recess and the second corner of the second substrate rests in the second raised recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover, and the positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover. The elevation of the platform region defines a first plane, and the second substrate is placed in the second plane. The first axis and the second axis are angularly aligned within a range of less than two degrees of rotation. The second plane is parallel to the first plane within a range of less than two degrees of inclination. In one or more embodiments, the first substrate belongs to a first MEMS component, and the first MEMS component includes a block suspended above the first substrate.

[0009] In one or more embodiments, the platform surface is disposed within a recess formed in the cover. In one or more embodiments, a notch feature is at least partially disposed within the recess formed in the cover.

[0010] In one or more embodiments, the method also includes: placing a certain volume of the tube core attachment material in the alignment area, which is configured to deform or flow during a bonding process of bonding the second substrate to the cover; and performing the bonding process; wherein the thickness of the tube core attachment material after performing the bonding process corresponds to the first height below the second substrate.

[0011] In one or more embodiments, the method also includes: patterning a certain volume of the tube core attachment material on the rear surface of the second substrate, which is configured to deform or flow during a bonding process of bonding the second substrate to the cover, wherein the tube core attachment material is not present at the corners of the second substrate in the rear surface of the second substrate; and performing the bonding process; wherein the thickness of the tube core attachment material after performing the bonding process corresponds to the first height below the second substrate.

[0012] In another example embodiment, a device includes a cover disposed over and coupled to a first substrate. An alignment region is formed on a top surface of the cover. The alignment region includes platform surfaces at four corners of the alignment region, the platform surfaces extending to a first height above the top surface of the cover within the alignment region. The alignment region also includes: a first raised recess partially surrounding the first platform surface at a first corner of the alignment region and extending above the first platform surface; and a second raised recess partially surrounding the second platform surface at a second corner of the alignment region diagonally opposite to the first corner and extending above the second platform surface. A second substrate is disposed within the alignment region so that the corners of the second substrate rest on corresponding platform regions in the alignment region, wherein the first corner of the second substrate rests within the first raised recess, and the second corner of the second substrate rests within the second raised recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover, and the positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover. The elevation of the platform region defines a first plane, and the second substrate is disposed within the second plane. The first axis and the second axis are angularly aligned within a range of less than two degrees of rotation. The second plane is parallel to the first plane within a range of less than two degrees of inclination. In one or more embodiments, the first substrate belongs to a first MEMS component, and the first MEMS component includes a block suspended above the first substrate.

[0013] In one or more embodiments, the platform surface is disposed within a recess formed in the cover. In one or more embodiments, the notch feature is disposed within the recess formed in the cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present disclosure is illustrated by examples, embodiments, etc. and is not limited by the accompanying drawings, in which like reference numerals indicate similar elements. The elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. According to the present disclosure, the accompanying drawings, together with the detailed description, are incorporated into and form a part of the specification to further illustrate examples, embodiments, etc. and to explain various principles and advantages, wherein:

[0015] Figure 1 is a perspective view of an example apparatus in which embodiments disclosed herein may be practiced.

[0016] Figure 2 Elements of an example assembly are shown according to one or more embodiments.

[0017] Figure 3 Describes a method suitable for forming a Figure 2 Steps in example processes of assemblies and similar devices.

[0018] Figure 4 Another example assembly is shown in accordance with one or more embodiments.

[0019] Figure 5 Elements of another example assembly are shown in accordance with one or more embodiments.

[0020] Figure 6 Describes a method suitable for forming a Figure 5 Cross-sectional views at various steps in an example process of an assembly of and similar assemblies.

[0021] Figure 7 is a perspective view of another cover according to one or more embodiments. DETAILED DESCRIPTION

[0022] The following detailed description provides examples for the purpose of understanding and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background or the following detailed description.

[0023] For the sake of simplicity and clarity of illustration, the drawings show the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessary confusion of the present invention. In addition, the elements in the drawings are not necessarily drawn to scale. For example, the size of some elements or regions in the drawings may be enlarged relative to other elements or regions to help improve the understanding of the embodiments of the present invention.

[0024] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims can be used to distinguish similar elements, and are not necessarily used to describe a specific order or time sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present invention described herein can, for example, operate in an order different from the order shown or otherwise described herein. In addition, the terms "comprise", "include", "have" and any variants thereof are intended to cover non-exclusive inclusions, so that the process, method, article or device including a list of elements is not necessarily limited to these elements, but may include other elements that are not explicitly listed or inherent to such processes, methods, articles or devices. The term "coupled" used herein is defined as being connected directly or indirectly in an electrical or non-electrical manner. As used herein, the terms "substantial" and "substantially" refer to being sufficient to achieve the purpose in a practical manner, and minor defects (if any) are not important for the purpose.

[0025] 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 illustrative purposes with reference to the orientation of the corresponding figure or figures.

[0026] It should be appreciated that the steps of the various processes described herein are non-limiting examples of suitable processes according to embodiments and are intended to be illustrative. Systems and devices according to embodiments herein may use any suitable process, including those that omit the steps described herein, perform those steps in a different order, and similar steps, etc. It should also be appreciated that well-known features may be omitted for clarity.

[0027] 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 formed from devices 110, 130, 150 to carrier substrate 104 and from carrier substrate 104 to lead frame 102. Device 100 may be configured to function 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 being orthogonal as possible to ensure the accuracy of device 100). However, when devices 110, 130, 150 are assembled together to form device 100, they may be misaligned. In some previous methods, alignment accuracy is limited by the accuracy of the automated assembly system. Thus, embodiments herein provide devices and methods that include mechanical features that enable improved registration of one device relative to another device using conventional assembly equipment.

[0028] Figure 2 Elements of an example assembly according to one or more embodiments are shown. Assembly 200 includes a device 210 coupled to a die 230. In this non-limiting example, device 210 is a microelectromechanical system (MEMS) device, such as an accelerometer, which includes a mass 214 suspended above a substrate 212. Cover 220 is bonded to substrate 212 via spacers 215 to protect mass 214. Cover 220 has an alignment recess (i.e., recess 222) that is configured to receive die 230 and includes features described further below that can be used to control the rotational alignment of die 230 relative to cover 220 and device 210. The cross-sectional view of assembly 200 corresponds to a line that vertically 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.

[0029] 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 opposed to 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, as shown in the schematic diagram, the rotation of the die 230 within the recess 222 is limited by the angle 299 between the axis 290 passing through the vertex of each notch at the corner regions 224a, b and the axis 295 passing through the corresponding corner of the die 230. The wall of the recess 222 surrounding each notch need not be stepped. For example, the walls of recess 222 may be rounded, as indicated by the dashed lines in corner region 224a, or may have any other suitable shape. Figure 2 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 2 Axes 290, 295 are for illustration purposes only.

[0030] 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 another device (e.g., die 230). For example, it is understood that the width of a recess when 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) is only slightly greater than Figure 2 The diagonal width of the die positioned in the recess shown, the angular range of motion of the die will be relatively small. Meanwhile, if the recess is enlarged relative to the die, the angular range of motion of the die will become larger.

[0031] The size of the recess relative to the substrate intended to be placed in the recess may 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 collectively configured 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 predetermined limits between one degree of rotation and two degrees of rotation, which may also depend on the capabilities of the die placement equipment employed by the user. In one or more embodiments, the distance from the vertex of one notch to the second notch (e.g., from the vertex of the notch at corner region 224a to the vertex of the notch at corner region 224b) is less than 2% greater than the distance between the corresponding corners of the die when the die is placed in the recess. It should be understood that the relative size of the recess relative to the die may vary based on the absolute size of the die. Recesses according to embodiments herein may be sized to accommodate a typical device die. For example, as a non-limiting example, the depth of the recess may be in the range of 50-100 μm.

[0032] Figure 3 Describe suitable for forming Figure 2 The process 300 includes steps 310, 320, 330, 340, 350, and 360, which are described below with respect to the components of the assembly 200. It should be appreciated that in one or more embodiments, steps of the process 300 or similar steps may be omitted or replaced in any suitable manner not described herein. Figure 3 The order described is executed in the order.

[0033] At step 310, the device 210 (i.e., the substrate 212 having the proof mass 214 suspended above the substrate 212) is received. At step 320, a spacer 215 is formed on the substrate 212 adjacent to and above the proof mass 214. The spacer can be any suitable material. For example, in one or more embodiments, the spacers 215 are glass frits, while in one or more other embodiments, they are metallic materials, such as aluminum or germanium, that can form an alloy that bonds the cover 220 to the substrate 212. In one or more other embodiments, the spacers 215 can be an adhesive or other curable polymer precursor. It should be understood that in one or more alternative processes, the spacers 215 can be pre-existing features on the substrate 212 that are bonded to the cover 220 by any suitable method, including but not limited to known wafer bonding methods.

[0034] At step 330, the cap 220 is bonded to the substrate 212 via the spacer 215. The cap, such as the cap 220, can be formed of any suitable material. In one or more embodiments, the cap 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 cap, such as the cap 220, is formed of silicon oxide, silicon nitride, aluminum oxide, etc., such as glass or quartz.

[0035] At step 340, a recess 222 is formed in the cover 220, including Figure 2 The recesses 222 are shown in the corner regions 224a, 224b. The recesses 222 can be formed by any suitable process, including but not limited to a photolithography process, in which a mask 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 mask material. In one or more embodiments, the cover cap 220 can be directly patterned via a micromachining process such as laser ablation.

[0036] At step 350, die 230 is placed in recess 222 and coupled to cover 220 via any suitable method, including but not limited to bonding die 230 to cover 220 using an adhesive film, a curable polymer, solder, or other material (not shown). At step 360, assembly 200 is fully formed with die 230 secured to cover 220 within recess 222.

[0037] In one or more embodiments, recesses such as recess 222 are patterned in a cover such as cover 220 and then the cover is bonded to a substrate such as substrate 212 (ie, step 340 may be performed before step 330).

[0038] Figure 4Another example assembly according to one or more embodiments is shown. Similar to assembly 200, assembly 400 includes a device 410, which includes a substrate 412 and a mass 414 suspended above the substrate 412. A cover 420 is coupled to the substrate 412 by a spacer 415 (e.g., spacer 215), which is disposed adjacent to and above the mass 414. A die 430 is disposed within a recess 422 in the cover 420 and is coupled to the cover 420 via a die attach material 432. The cross-sectional view of assembly 400 corresponds to a line that vertically bisects the plan view of the top surface 421 of the cover 420. The dashed area within the recess 422 corresponds to the location of a protrusion in the wall of the 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 it is bonded to the cover 420, which can be referred to as Figure 4 This can be understood from the plan view of the cover 420 and the die 430 in FIG.

[0039] As shown, in a plan view of the cover 420, one suitable arrangement of the recess 422 is a rectangular shape with chamfered corners at the corner regions 424 (i.e., an octagonal recess). It should be understood that the protruding areas of the walls of the recess 422 in the corner regions 424 may have any suitable geometry (e.g., the chamfered portions shown may be rounded). The recess 422 has a smaller footprint 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, which is 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 above the recess 422 (i.e., above the corner region 424) on the top surface 421 of the cover 420. 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 over the recess on the cover 420. Thus, when the die 430 is placed directly over the recess 422, within the limits of the planarity of the top surface 421 of the cover 420 and the bottom surface 431 of the die 430, the bottom surface 431 of the die 430 will be aligned with the top surface of the cover 420 (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).

[0040] 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 before an assembly such as assembly 400 is completed.

[0041] 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 may 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, such as die 430. 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 die attach material 432, is a polymeric material, such as an epoxy compound, including but not limited to a conductive epoxy resin, such as a silver-containing epoxy resin.

[0042] Figure 5 Elements of an example assembly according to one or more embodiments are shown. Assembly 500 includes a device 510 coupled to a die 530. In this non-limiting example, device 510 is a microelectromechanical system (MEMS) device, such as an accelerometer, which includes a 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 mass 514. Cover 520 has an alignment recess (i.e., recess 522) configured to receive die 530. Recess 522 includes features that can be used to control the rotational alignment of die 530 relative to cover 520 (and device 510) as described further below, as well as features that ensure that die 530 is coplanar with a top surface 521 of cover 520 within limits of the flatness of a surface of cover 520 and a bottom surface of die 530. The cross-sectional view of assembly 500 corresponds to the line that vertically bisects the plan view of top surface 521 of cover 520. The dashed area within the cross section of recess 522 corresponds to the location of the protrusions in the wall of recess 522 that form the notch and the platform areas in corner area 524a and corner area 524c.

[0043] In a plan view of the top surface 521 of the cover 520, it can be seen that the recess 522 has corner areas 524a, 524b diagonally opposite to each other and corner areas 524c, 524d opposite to each other. All of the four corners 524 include a first depth (see FIG. 5 ) recessed relative to the top surface 521. Figure 5 The platform area of ​​the cross-sectional view of the corner region 524 has a depth D1) less than the depth of the recess 522 outside the corner region 524. The occupied space of these areas is Figure 5 The floor plan is hatched. These platform areas function similarly to Figure 4 The corner regions 424 of the recess 422 are formed in a manner that allows the corners of the die 530 to be supported above the bottom of the recess 522 .

[0044] In two of the corner regions 524 (corner regions 524a, 524b), the outer edges of the recess 522 protrude toward the center of the recess 522. Each of the corner regions 524a, 524b has a notch that is 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 function of the notches in the corner regions 524a, 524b is similar to Figure 2 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.

[0045] The die 530 may be bonded to the cover 520 similar to the die 430 bonded in the recess 422. That is, the die attach material 532 (e.g., die attach material 432) is patterned on the bottom surface 531 of the die 530 such that it is not present at the corners of the bottom surface 531 and has a footprint that is smaller than the footprint of the recess 522. The die attach material 532 is configured such that when the die 530 is lowered into the recess 522, the die attach material 532 will be compressed between the bottom surface 531 of the die 530 and the bottom of the recess 522, at which point the die attach material 532 will deform or flow under the die 530, further expanding into the recess 422 and away from the die 530. When the corners 534 of the die 530 are supported at the platform area (i.e., in the corner regions 524 of the recess 522) and sufficient downward pressure is applied, the die 530 tends to "self-level" within the recess 522, thereby ensuring that the bottom surface 531 of the die 530 is substantially coplanar with the top surface 521 of the cover 520 (i.e., the die 530 is not excessively tilted relative to the cover 520), and placing the two corners 534 of the die 530 within the notches in the corner regions 524a, 524b will ensure that the die 530 is angularly aligned with the cover 520 (and therefore angularly aligned with the device 510).

[0046] Figure 6 Describe suitable for forming Figure 5 5. The process 600 includes steps 610, 620, 630, 640, 650, which are described below with respect to the components of the assembly 500. It should be appreciated that in one or more embodiments, steps of the process 600 or similar steps may be omitted or modified in any suitable manner not described herein. Figure 6The order described is executed in the order.

[0047] At step 610, cover 520 is received. Cover 520 may be received as a separate part, or may have been bonded to substrate 512 of device 510. At step 620, portions of recess 522 outside the platform region of corner region 524 (i.e., portions of the recess having a Figure 5 The recess 522 may be formed by any suitable process, including but not limited to a photolithography process, in which a mask material (e.g., a photoresist) is patterned over the cover 520 and the cover 520 is selectively etched (e.g., using wet chemical etching or plasma etching) to form the recess 522 in the area not protected by the mask material. In one or more embodiments, the cover, such as the cover 520, may be directly patterned via a micromachining process, such as laser ablation, to form a recess, such as the recess 522.

[0048] 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 Figure 5 The formation of the terrace regions in the corner regions 524a, 524b also results in the formation of notches in the corner regions 524a, 524b.

[0049] At step 640, die 530 (shown with die attach material 532 on bottom surface 531) is contacted with cover 520 and seated within recess 522. Pressure or heat may be applied to deform die attach material 532, spreading from the center of die 530 toward the edge of recess 522.

[0050] Finally, at step 650, the die 530 is placed in the recess 522, with the corners 534 of the die 530 resting on the terrace 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.

[0051] It should be understood that in one or more embodiments, before the die is bonded to the cover, a die attach material such as die attach material 532 (e.g., die attach material 432) can be placed in a recess of the cover (e.g., recess 522 of cover 520) rather than the die attach material being placed on the die. It should also be understood that any suitable materials and processes can be used to bond the die to the cover according to embodiments herein. Thus, in one or more embodiments, the 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 a recess such as recess 522 and / or contacting a bottom surface of a die such as 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.

[0052] Figure 7 are cross-sectional and perspective views of a cover cap 720 that also enables a die to be bonded to the cover cap in a manner that allows both rotational alignment and tilt of the die relative to the cover cap 720 orientation to be controlled, according to one or more embodiments. Figure 7 In the example of FIG. 5 , cap 720 has a set of raised features on its top surface 721 that function similarly to the features of corner 524 of cap 520. However, cap 720 does not require a recess, such as recess 522. Features 724a, 724b are positioned diagonally opposite each other, similar to corner regions 524a, 524b of cap 520. Each of features 724a, 724b has a platform area extending to a height H1 indicated in the cross-sectional view, which is surrounded by a notched sidewall that extends above top surface 721 to a height H2 indicated in the cross-sectional view. The platform areas of features 724c, 724d also extend to a height H1 and are positioned diagonally opposite each other, similar to corner regions 524c, 524d of cap 520, and serve as additional platform areas for a die, such as die 530.

[0053] example

[0054] Features of the embodiments may be understood with the aid of one or more of the following examples:

[0055] Example 1: An apparatus or method comprising placing a cover over a first substrate and coupling the cover to the first substrate. An alignment recess is formed in a top surface of the cover. The alignment recess has a first length and a first width at a center of the alignment recess. The alignment recess has a second length less than the first length and a second width less than the first width at each of four corner regions of the alignment recess. A second substrate is placed over the alignment recess on the top surface of the cover. The second substrate has a third length greater than the second length and a third width greater than the second length. A die attach material is filled in a portion of the alignment recess so that the corners of the second substrate rest on a surface of the cover, surround the alignment recess, and the second substrate is bonded to the cover via the die attach material within the alignment recess.

[0056] Example 2: The apparatus or method of Example 1, wherein the first substrate includes a first microelectromechanical system (MEMS) component thereover, the first MEMS component including a mass suspended above the first substrate.

[0057] Example 3: The apparatus or method of Example 1 or Example 2, further comprising a volume of the die attach material disposed within the alignment recess, configured to deform or flow during a bonding process of bonding the second substrate to the cover lid. The volume of the die attach material is less than a total volume of the alignment recess.

[0058] Example 4: The apparatus or method of Example 3, wherein the bonding process is a thermocompression bonding process or a solder reflow process.

[0059] Example 5: The apparatus or method of any one of Examples 1-4, further comprising a volume of the die attach material patterned on the rear surface of the second substrate, configured to deform or flow during a bonding process of bonding the second substrate to the cover lid. The die attach material is not present in the rear surface of the second substrate at a corner of the second substrate.

[0060] Example 6: The apparatus or method of any of Examples 1-5, further comprising forming the alignment recess before coupling the cover to the first substrate.

[0061] Example 7: The apparatus or method of any of Examples 1-5, further comprising forming the alignment recess after coupling the cover to the first substrate.

[0062] Example 8: The device or method according to any one of Examples 1-7, further comprising forming a second alignment recess in the top surface of the second substrate. The second alignment recess has a fourth length and a fourth width at the center of the second alignment recess. The alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of the four corner regions of the second alignment recess. A third substrate is disposed on the top surface of the second substrate above the second alignment recess, the third substrate having a sixth length greater than the fifth length and a sixth width greater than the fifth length. A die attach material is made to fill a portion of the second alignment recess so that the corners of the third substrate rest on the surface of the second substrate, surrounding the alignment recess, and the third substrate is bonded to the second substrate through the die attach material within the second alignment recess.

[0063] Example 9: The device or method according to any one of Examples 1-7, further comprising a second cover cap disposed above the second substrate. A second alignment recess is formed in the top surface of the second cover cap. The second alignment recess has a fourth length and a fourth width at the center of the second alignment recess. The alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of the four corner regions of the second alignment recess. A third substrate is disposed on the top surface of the second cover cap above the second alignment recess. The third substrate has a sixth length greater than the fifth length and a sixth width greater than the fifth length. A die attach material is made to fill a portion of the second alignment recess so that the corners of the third substrate rest on the top surface of the second cover cap, surround the second alignment recess, and the third substrate is bonded to the second cover cap through the die attach material within the second alignment recess.

[0064] Example 10: A method or apparatus comprising: positioning a cover over a first substrate and coupling the cover to the first substrate. An alignment region is formed on a top surface of the cover. The alignment region includes platform surfaces at four corners of the alignment region, the platform surfaces extending within the alignment region to a first height above the top surface of the cover. The alignment region also includes: a first raised recess partially surrounding the first platform surface at a first corner of the alignment region and extending above the first platform surface; and a second raised recess partially surrounding the second platform surface at a second corner of the alignment region diagonally opposite the first corner and extending above the second platform surface. A second substrate is positioned within the alignment region so that the corners of the second substrate rest on corresponding platform areas in the alignment region, wherein the first corner of the second substrate rests within the first raised recess and the second corner of the second substrate rests within the second raised recess. The positions of the first recess and the second recess define a first axis parallel to the top surface of the cover, and the positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover. The elevation of the platform region defines a first plane, and the second substrate is disposed in a second plane.

[0065] Example 11: An apparatus or method according to Example 10, wherein the first axis and the second axis are angularly aligned within a range of one to two degrees of rotation.

[0066] Example 12: The apparatus or method of Example 10, wherein the first axis and the second axis are angularly aligned within a range of less than one degree of rotation; and

[0067] Example 13: The device or method of any one of Examples 10-12, wherein the second plane is parallel to the first plane within a range of one to two degrees of inclination.

[0068] Example 14: The device or method of any one of Examples 10-12, wherein the second plane is parallel to the first plane within a range of less than one degree of inclination.

[0069] Example 15: The apparatus or method of any of Examples 10-14, wherein the first substrate comprises a first microelectromechanical system (MEMS) component, the first MEMS component comprising a mass suspended above the first substrate.

[0070] Example 16: The device or method of any of Examples 10-15, wherein the platform surface is disposed within a recess formed in the cover.

[0071] Example 17: The device or method of any of Examples 10-16, wherein the notch feature is at least partially disposed within the recess formed in the cover.

[0072] Example 18: The apparatus or method of any of Examples 10-17, further comprising a volume of the die attach material placed within the alignment region, configured to deform or flow during a bonding process of bonding the second substrate to the cover lid, wherein a thickness of the die attach material after performing the bonding process corresponds to the first height below the second substrate.

[0073] Example 19: The apparatus or method of any one of Examples 10-17, further comprising a volume of the die attach material patterned on the rear surface of the second substrate, configured to deform or flow during a bonding process of bonding the second substrate to the cover lid. The die attach material is absent from the corners of the second substrate in the rear surface of the second substrate. The thickness of the die attach material after performing the bonding process corresponds to the first height below the second substrate.

[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 is not necessarily to be construed as preferred or advantageous over other embodiments. In addition, it is not intended to be bound by any express or implied theory presented in the foregoing technical field, background technology, or detailed description.

[0075] It should be understood that the application of the present invention is not limited to the details of the construction and the arrangement of components described in the foregoing description or shown in the accompanying drawings. The present invention can have other embodiments and can be practiced or implemented in various ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered as limiting. "Including", "comprising" or "having" and their variants used herein are intended to cover the items listed later and their equivalents and additional items. Unless otherwise specified or limited, the terms "mount", "connect", "support" and "couple" and their variants 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 make and use embodiments of the present invention. It will be clear to those skilled in the art that various modifications to the illustrated embodiments are present, and the general principles herein may be applied to other embodiments and applications without departing from embodiments of the present invention. Therefore, embodiments of the present invention are not intended to be limited to the illustrated embodiments, but are given the widest scope consistent with the principles and features disclosed herein. The foregoing detailed description will be read with reference to the accompanying drawings, in which similar elements in different drawings have similar reference numerals. The drawings, 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 fall within the scope of embodiments of the present invention.

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

[0078] The above description refers to elements or nodes or features that are "connected" or "coupled" together. As used herein, unless otherwise expressly stated, "connected" refers to one element being directly engaged (or in direct communication) with another element, and not necessarily mechanically engaged. Similarly, unless otherwise expressly stated, "coupled" refers to one element being directly or indirectly engaged (or communicating directly or indirectly electrically or otherwise) with another element, and not necessarily mechanically engaged. Therefore, although the schematic diagrams shown in the figures 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 over a first microelectromechanical system (MEMS) component, the first MEMS component comprising a mass suspended above a first substrate, and coupling the cover to the first substrate; forming an alignment recess in a top surface of the cover, wherein the alignment recess has a first length and a first width at a center of the alignment recess; and wherein the alignment recess has a second length less than the first length and a second width less than the first width at each of four corner regions of the alignment recess; disposing a second substrate on the top surface of the cover over the alignment recess, the second substrate having a third length greater than the second length and having a third width greater than the second length; as well as The die attach material fills a portion of the alignment recess such that a corner of the second substrate rests on a surface of the cover lid surrounding the alignment recess and the second substrate is bonded to the cover lid through the die attach material within the alignment recess.

2. The method according to claim 1, characterized in that Also includes: placing a volume of the die attach material within the alignment recess configured to deform or flow during a bonding process of bonding the second substrate to the cover lid; Wherein a volume of the die attach material is smaller than a total volume of the alignment recess.

3. The method according to claim 1, characterized in that Also includes: patterning a volume of the die attach material on a rear surface of the second substrate configured to deform or flow during a bonding process of bonding the second substrate to the cover lid; Wherein the die attach material is absent in the back surface of the second substrate at corners of the second substrate.

4. The method according to claim 1, characterized in that Also includes: forming a second alignment recess in the top surface of the second substrate, wherein the second alignment recess has a fourth length and a fourth width at a center of the second alignment recess; and wherein the alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of four corner regions of the second alignment recess; disposing a third substrate on the top surface of the second substrate over the second alignment recess, the second substrate having a sixth length greater than the fifth length and having a sixth width greater than the fifth length; as well as Filling a portion of the second alignment recess with a die attach material such that corners of the third substrate rest on a surface of the second substrate surrounding the alignment recess and the third substrate is bonded to the second substrate through the die attach material within the second alignment recess.

5. A micro-electromechanical system (MEMS) device, characterized in that: include: a first MEMS assembly including a mass suspended above a first substrate and coupling a cap to the first substrate; a cover coupled to the first substrate and disposed over the mass of the first MEMS component; an alignment recess formed at a top surface of the cover, wherein the alignment recess has a first length and a first width at a center of the alignment recess; and wherein the alignment recess has a second length less than the first length and a second width less than the first width at each of four corner regions of the alignment recess; a second substrate disposed on the top surface of the cover over the alignment recess, the second substrate having a third length greater than the second length and having a third width greater than the second length; as well as wherein the second substrate is bonded to the cover lid within the alignment recess by a die attach material disposed within the recess, such that a corner of the second substrate rests on a surface of the cover lid, surrounding the alignment recess, and the second substrate is bonded to the cover lid by the die attach material within the alignment recess.

6. The device according to claim 5, characterized in that The die attach material is absent in the back surface of the second substrate at corners of the second substrate.

7. The device according to claim 5, characterized in that Also includes: a second alignment recess formed at a top surface of the second substrate, wherein the second alignment recess has a fourth length and a fourth width at a center of the second alignment recess; and wherein the alignment recess has a fifth length smaller than the fourth length and a fifth width smaller than the fourth width at each of four corner regions of the second alignment recess; a third substrate disposed on the top surface of the second substrate over the second alignment recess, the third substrate having a sixth length greater than the fifth length and having a sixth width greater than the fifth length; as well as A die attach material fills a portion of the second alignment recess so that a corner of the third substrate rests on a surface of the second substrate, surrounds the second alignment recess, and the third substrate is bonded to the second substrate through the die attach material within the second alignment recess.

8. The device according to claim 5, characterized in that Also includes: a second cover disposed over and coupled to the second substrate; a second alignment recess formed in the top surface of the second substrate, wherein the second alignment recess has a fourth length and a fourth width at a center of the second alignment recess; and wherein the alignment recess has a fifth length less than the fourth length and a fifth width less than the fourth width at each of four corner regions of the second alignment recess; disposing a third substrate on the top surface of the second substrate over the second alignment recess, the third substrate having a sixth length greater than the fifth length and having a sixth width greater than the fifth length; as well as A die attach material forms part of the second alignment recess such that corners of the third substrate rest on the top surface of the second cover lid, surround the second alignment recess, and the third substrate is bonded to the second substrate through the die attach material within the second alignment recess.

9. A method, characterized in that include: disposing a cover over a first microelectromechanical system (MEMS) component, the first MEMS component comprising a mass suspended above a first substrate, and coupling the cover to the first substrate; An alignment area is formed on the top surface of the cover, the alignment area comprising: platform surfaces at four corners of the alignment region extending within the alignment region to a first height above the top surface of the cover; a first raised recess partially surrounding and extending above the first platform surface at a first corner of the alignment region; and a second raised recess partially surrounding and extending above the second platform surface at a second corner of the alignment region diagonally opposite the first corner; and positioning a second substrate in the alignment region such that corners of the second substrate rest on corresponding land regions in the alignment region, wherein a first corner of the second substrate rests within the first raised recess and a second corner of the second substrate rests within the second raised recess; wherein the positions of the first raised recess and the second raised recess define a first axis parallel to the top surface of the cover, and the positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover; wherein the first axis and the second axis are angularly aligned within a range of less than two degrees of rotation; and The elevation of the platform region defines a first plane, and the second substrate is disposed in a second plane, the second plane being parallel to the first plane within a range of less than two degrees of inclination.

10. A first micro-electromechanical system (MEMS) device, characterized in that: include: a cover disposed over a first MEMS component, the first MEMS component comprising a block suspended over a first substrate and coupling the cover to the first substrate; an alignment region formed on the top surface of the cover, the alignment region comprising: platform surfaces at four corners of the alignment region extending within the alignment region to a first height above the top surface of the cover; a first raised recess partially surrounding and extending above the first platform surface at a first corner of the alignment region; and a second notch feature partially surrounding and extending above a second platform surface at a second corner of the alignment region diagonally opposite the first corner; and a second substrate disposed in the alignment region such that corners of the second substrate rest on corresponding land regions in the alignment region, wherein a first corner of the second substrate rests within the first raised recess and a second corner of the second substrate rests within a second raised recess; wherein the positions of the first notch and the second notch define a first axis parallel to the top surface of the cover, and the positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover; wherein the first axis and the second axis are angularly aligned within a range of less than two degrees of rotation; and The elevation of the platform region defines a first plane, and the second substrate is disposed in a second plane, the second plane being parallel to the first plane within a range of less than two degrees of inclination.

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