Transducer assembly and method of manufacturing a micro-electromechanical system microphone assembly

Abstract

The present disclosure relates to a transducer assembly and a method of manufacturing a micro-electromechanical system microphone assembly, wherein the transducer assembly includes a base. The transducer assembly may include a stress isolation support disposed on the base. The transducer assembly may include a micro-electromechanical system die disposed on the stress isolation support. The transducer assembly may include a die bonding adhesive disposed between the micro-electromechanical system die and the base, and the die bonding adhesive may bond the micro-electromechanical system die to the base. The stress isolation support may be embedded in the die bonding adhesive between the base and the micro-electromechanical system die.

Description

Technical Field

[0001] The present disclosure relates to methods and apparatus for transducer assemblies having a standoff. More particularly, the present disclosure relates to transducer assemblies including a MEMS (Microelectromechanical Systems) die on a standoff. Background Art

[0002] Currently, consumer electronic devices such as mobile phones, personal computers, smart speakers, hearing aids, True Wireless Stereo (TWS) headsets, and other host devices often incorporate one or more small microphones and / or sensors. Advances in micro- and nano-fabrication technology have led to the development of microphones and sensors of increasingly smaller sizes and different form factors. For example, capacitive MEMS microphones have replaced the once-dominant electret microphones in these and other applications due to their low cost, small size, and high sensitivity. Summary of the invention

[0003] According to one aspect of the present disclosure, the present disclosure relates to a transducer assembly, which includes: a base; a stress isolation support, which is placed on the base; a micro-electromechanical system die, which is arranged on the stress isolation support; and a die bonding adhesive, which is arranged between the micro-electromechanical system die and the base, and the die bonding adhesive bonds the micro-electromechanical system die to the base, and the stress isolation support is embedded in the die bonding adhesive between the base and the micro-electromechanical system die.

[0004] According to another aspect of the present disclosure, the present disclosure relates to a method for manufacturing a micro-electromechanical system microphone assembly, the method comprising the following steps: providing a stress isolation support on a first surface of a base, wherein a micro-electromechanical system die will be arranged in the first surface of the base, the first surface being opposite to a second surface of the base; depositing a die bonding adhesive on the base including an area where the stress isolation support is placed; and placing the micro-electromechanical system die onto the die bonding adhesive and the stress isolation support, wherein the die bonding adhesive bonds the micro-electromechanical system die to the base, and the stress isolation support is placed between the micro-electromechanical system die and the first surface of the base. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In order to describe the manner in which the advantages and features of the present disclosure can be obtained, the description of the present disclosure is presented by reference to the specific embodiments of the present disclosure illustrated in the accompanying drawings. These drawings depict only example embodiments of the present disclosure and are therefore not to be considered as limiting the scope thereof. For clarity, the accompanying drawings may have been simplified and are not necessarily drawn to scale.

[0006] Figure 1 and Figure 2 are example top views of a transducer subassembly at various stages of assembly according to possible implementations;

[0007] Figure 3 is an example side cross-sectional view of a portion of a transducer subassembly according to a possible implementation;

[0008] Figure 4 is an example plan view of a transducer subassembly according to a possible implementation;

[0009] Figure 5 is an example side view of a transducer assembly in the form of a sensor package according to a possible implementation; and

[0010] Figure 6 is an example flow chart illustrating operations for providing a stress isolation standoff for a MEMS die, according to a possible implementation. DETAILED DESCRIPTION

[0011] Embodiments provide methods and apparatus for a transducer assembly having a support. According to possible embodiments, the transducer assembly may include a base. The transducer assembly may include a stress isolation support located on the base. The transducer assembly may include a MEMS die disposed on the stress isolation support. The transducer assembly may include a die bonding adhesive disposed between the MEMS die and the base, the die bonding adhesive may bond the MEMS die to the base. The stress isolation support may be embedded in the die bonding adhesive between the base and the MEMS die.

[0012] Figure 1 and Figure 2 is an example top view of a portion of a transducer subassembly 100 according to a possible implementation, wherein: Figure 1 1 shows a schematic diagram of a transducer subassembly 100 including a base 110 without a MEMS die, and Figure 2 A schematic diagram of a transducer subassembly 100 including a base 110 having a MEMS die 130 is shown.

[0013] Figure 3 is an example side view of a transducer subassembly 300 according to a possible implementation. Figure 4is an example top view of a transducer subassembly 400 according to a possible implementation. Figure 5 is an example side view of a transducer assembly in the form of a sensor package 500 according to a possible implementation.

[0014] exist Figures 1 to 5 In the embodiment of the present invention, the transducer assembly may include a base 110 on which the transducer may be mounted. Figure 1 as well as Figures 3 to 5 In the embodiment of the present invention, the transducer assembly may include a stress isolation support 120 disposed on the base 110. According to possible embodiments, the stress isolation support 120 may have an elastic modulus of less than 100 MPa at room temperature. For example, the stress isolation support 120 may provide stress isolation by being soft, because it may have an elastic modulus of less than about 100 MPa (megapascals), less than 10 MPa, or other useful elastic modulus at room temperature, which may be a softness range that can be used to stress isolate the MEMS die 130 from the base 110 (such as a base substrate) to reduce the effect of stress (such as slight twisting, slight bending, and other stresses) from the MEMS die 130 on the base 110. According to possible embodiments, the stress isolation support 120 may also have a Shore A hardness of less than 75 or other useful Shore A hardness for providing stress isolation.

[0015] The transducer assembly may include a transducing component or transducer disposed on a stress isolation mount. Figure 3 and Figure 4 A capacitive MEMS transducer 130 is shown mounted on a support 120. In other embodiments, the transducer may be some other capacitive or non-capacitive transducing component, such as a piezoelectric MEMS, optical sensor, and other transducing components that may benefit from stress isolation.

[0016] The depth from the base 110 (such as the height or thickness of the stress isolation standoff 120) may depend on the size of the transducer assembly, may depend on the size of the transducer (such as the size and thickness of the MEMS die 130), may depend on the properties of the die attach adhesive, may depend on the amount of stress isolation desired, and / or may depend on other properties of the transducer assembly.

[0017] In some transducer assemblies, the stress isolation standoff 120 may have a depth of at least 15 μm, may have a goal of 50 μm to 70 μm, may have a goal of approximately 50 μm + / - 10 μm, or may have any other useful depth. 2 With 4mm 2Some transducer assemblies of the MEMS die 130 between may use a stress isolation standoff 120 height of at least 25 μm. Softer materials for the stress isolation standoff 120 may be effective in the lower range (eg, 15 μm to 20 μm).

[0018] The transducer assembly may include a die attach adhesive 140 disposed between the MEMS die 130 and the base 110. The die attach adhesive 140 may bond the MEMS die 130 to the base 110. The stress isolation standoff 120 may be embedded in the die attach adhesive 140 between the base 110 and the MEMS die 130.

[0019] According to possible implementations of the transducer assembly 100, the stress isolation support 120 may include a plurality of stress isolation supporters disposed between the MEMS die 130 and the base 110. For example, the plurality of stress isolation supporters may include at least three pillars, bumps or other forms of stress isolation supporters.

[0020] According to possible implementations of the transducer assembly, the stress isolation support 120 may have a rectangular shape deposited on the base 110. The rectangular shape may be square, may have rounded edges, may have chamfered corners, may be slightly trapezoidal, or may be any other shape that takes a general rectangular shape. The stress isolation support may also take other shapes, such as circular, polygonal, or other closed or open shapes.

[0021] Reference Figure 3 The transducer assembly 300 can be configured such that the MEMS die 130 is arranged in a rectangular shape (eg Figure 4 The die attach adhesive 140 formed in a rectangular shape or other shape is bonded to the base 110, such as shown on the transducer assembly 400 of FIG. 1 . The die attach adhesive 140 may be formed in a rectangular shape or other shape, regardless of whether the stress isolation standoffs 120 are multiple stress isolation standoffs, a continuous line of stress isolation standoffs, or a semi-continuous line of stress isolation standoffs (such as when a rectangular shape or other shape is used). For example, the die attach adhesive 140 may also take other shapes, such as a circle, a polygon, or other closed or open shapes. The die attach adhesive may be deposited in a rectangular shape or other shape by jetting an adhesive line, depositing multiple dots of adhesive, dispensing a rectangular shape using an adhesive, or any other way of creating a rectangular or other shaped adhesive.

[0022] Reference Figure 5, the transducer assembly may be a sensor package 500, which may include a housing 510, such as a cover or can, disposed on a base 110. The housing may surround the MEMS die 130 between the housing 510 and the base 110. The sensor package 500 may include an external device interface 520 disposed on the base 110. The external device interface may be implemented as a surface mount interface, or may include leads configured for through-hole mounting on a host device.

[0023] The sensor package 500 may include an integrated circuit 530, such as an application specific integrated circuit (ASIC), which is electrically coupled to the MEMS die 130 and the contacts of the external device interface 520, for example, via electrical leads 534 and / or leads passing through the base 110. The integrated circuit 530 may receive electrical signals from the MEMS die 130, for example, via electrical leads 532, and may communicate with a host device, for example, via electrical leads 534 and / or leads in the base 110, by using the contacts of the external device interface 520. According to a possible implementation, the integrated circuit 530 may be covered by a protective coating 526.

[0024] The external device interface 520 may be disposed on a surface 522 of the base 110, which is on a side of the base 110 opposite to a surface 524 of the base 110 in which the stress isolation support 120 and the MEMS die 130 are disposed. According to a possible embodiment, the plane of the stress isolation support 120 may allow the bottom plane 138 ( Figure 3 The transducer assembly 300 (shown in FIG. 1 ) is horizontally adjusted to be substantially parallel to the surface 524 of the base 110.

[0025] According to a possible implementation, the base 110 may include an acoustic port 150. The MEMS die 130 may be acoustically coupled to the acoustic port 150. For example, the acoustic port 150 may be a hole in the base 110 that allows sound to pass through the base to the MEMS die 130. The stress isolation standoff 120 may be at least one stress isolation standoff, and the die attach adhesive 140 may at least partially surround the acoustic port 150.

[0026] The illustrated embodiment may be considered a bottom port embodiment, but the acoustic port 150 may be placed at other locations on the transducer assembly. For example, the acoustic port 150 may also be on the housing 510 of a top port transducer assembly. The acoustic port 150 may also be on one side of the transducer assembly, may be anywhere else on the transducer assembly, or may not have an acoustic port 150 for a sensor such as a MEMS die vibration sensor or other sensor.

[0027] According to a possible implementation, the MEMS die 130 may include a MEMS die substrate 132 coupled to the base 110 via the stress isolation standoff 120 and the die attach adhesive 140. The MEMS die 130 may include a back plate 134 coupled to the MEMS die substrate 132. The MEMS die 130 may include a diaphragm 136 coupled to the MEMS die substrate 132. The diaphragm 136 may be movably disposed relative to the back plate 135.

[0028] The diaphragm 136 can be acoustically coupled to the acoustic port 150. A backplate 134 can be disposed on the MEMS die substrate 132 on the side of the diaphragm 136 opposite the acoustic port 150. The diaphragm 136 and backplate architecture can vary depending on the MEMS transducer or other transducer or die type. For example, a stress isolation mount can be used for any transducing component that can benefit from stress isolation. Such MEMS dies can include: a transducer in which the diaphragm 136 and the backplate 134 are reversed, a transducer having a diaphragm between two backplates, a transducer having two diaphragms around a backplate, a transducer having a piezoelectric MEMS, and / or other MEMS dies. According to a possible implementation, the volume on the acoustic port 150 side of the diaphragm 136 can be considered as the front cavity volume 162, and the volume on the opposite side of the diaphragm 136 can be considered as the back cavity volume 164.

[0029] Figure 6 6 is an example flow chart illustrating the operation of setting a stress isolation standoff for a MEMS die or any other transducer according to possible implementations. At 610, a stress isolation standoff may be set on a first surface of a base in which the MEMS die will be placed. The first surface may be opposite to a second surface of the base. The stress isolation standoff may be primarily set (such as created) at locations where the MEMS die will contact the base, for example, in a pattern that matches the area where the MEMS die will contact the base via the standoff. According to possible implementations, the stress isolation standoff may have an elastic modulus of less than 100 MPa at room temperature.

[0030] According to a possible implementation, the MEMS die may include contact areas contacting the die attach adhesive. The step of providing stress isolation standoffs may include creating the stress isolation standoffs in a pattern at least partially matching the contact areas of the MEMS die.

[0031] According to possible embodiments, the step of providing a stress isolation support may include at least any one of the following: screen printing, spraying or needle dispensing a stress isolation support on a first surface on the base. Moreover, any method of depositing a liquid or paste adhesive on a substrate such as a base can be used to provide (such as create) a soft support. According to possible embodiments, after depositing a liquid or paste adhesive to form a soft support, the adhesive can be cured and a die bonding adhesive can be deposited on a base including an area where a cured stress isolation support is placed. According to other possible embodiments, the stress isolation support can be grown on the base, deposited as a point on the base, or otherwise provided on the base. For example, according to possible embodiments, the stress isolation support may include a plurality of stress isolation supports provided between a MEMS die (such as a MEMS die substrate) and a base.

[0032] According to a possible implementation, the stress isolation standoff may have a rectangular shape deposited on the base. For example, the rectangular shape may be a square, may have rounded edges, may have chamfers, or may be any other shape that takes a general rectangular shape. As another example, the step of depositing a die attach adhesive may include depositing a die attach adhesive in a rectangular shape on the base. The MEMS die may be bonded to the base via the die attach adhesive in a rectangular shape.

[0033] At 620, a die attach adhesive may be deposited on the base including the area where the stress isolation standoffs are disposed. At 630, a MEMS die may be placed on the die attach adhesive and the stress isolation standoffs. The die attach adhesive may bond the MEMS die to the base with the stress isolation standoffs disposed between the MEMS die and the first surface of the base. According to a possible implementation, an external device interface having electrical contacts may be formed on a second surface of the base.

[0034] According to at least some embodiments, the standoffs can provide: Isolation of a MEMS die or any other transducer from its package. The standoffs can be pre-patterned on a base, such as a substrate, with high throughput and low cost while maintaining conventional MEMS die placement methods. The standoffs can have a substantially uniform height so that the base of the MEMS die is coplanar with the surface of the substrate.

[0035] Embodiments may apply to both unconstrained and constrained diaphragms. Unconstrained diaphragms can typically only be attached at one or two locations. Constrained diaphragms (such as tensioned diaphragms) can be attached around the entire perimeter of the diaphragm. Embodiments may also cover variations in transducer design. For example, some transducers may have two diaphragms, may have backplates on different sides of the diaphragms, may have a diaphragm between two backplates, may have two diaphragms and a backplate, may be piezoelectric MEMS, and / or may have or may be other variations of transducers.

[0036] Embodiments may provide discrete standoffs that may be formed on a substrate, and the die attach adhesive may be deposited on the standoffs and the substrate. The standoffs may be deposited by screen printing, or otherwise deposited or formed prior to depositing the die attach adhesive. The standoffs may be discrete dots, or may be single or multiple lines of standoff material placed on the substrate in a pattern that matches the areas of the bottom of the transducer that will contact the standoffs and adhesive.

[0037] According to at least some embodiments, MEMS microphone dies and other MEMS dies (such as pressure sensors or other sensors) can use a soft core attach material with sufficient bond line thickness to achieve stress isolation to achieve desired performance. A soft support such as a stress isolation support can set the bond line of the MEMS die. Points of soft material under the die can set the bond line. These soft material points can be screen printed, sprayed, needle-dispensed, or otherwise placed or formed on the surface. Photolithography can also be performed using soft materials. Other shapes other than points can also be used. Additional soft core attach material can be used above and around the soft support to bond the die to the surface.

[0038] At least some of the methods of the present disclosure may be implemented on a programmed processor. However, the circuits, flow charts, and operations may also be implemented on general or special purpose computers, programmed microprocessors or microcontrollers, and peripheral integrated circuit components, integrated circuits, hardware electronic devices, or logic circuits (such as discrete component circuits, programmable logic devices, etc.). In general, any device that has a finite state machine capable of implementing the flow charts shown in the figures can be used to implement the processor functions of the present disclosure.

[0039] Moreover, although the present disclosure has been described with respect to its specific embodiments, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, in other embodiments, various components of the embodiments may be interchanged, added, or replaced. Moreover, all elements of the various drawings are not necessary for the operation of the disclosed embodiments. For example, it will enable a person of ordinary skill in the field of the disclosed embodiments to carry out and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than limiting. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0040] In this document, relational terms such as "first", "second", etc. can be used alone to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship, or the order between such entities and actions. The phrases "at least one of...", "at least one of the group selected from...", or "at least one of the selected from..." following a list are defined to refer to one element, some elements, or all but not necessarily all elements of the elements in the list. The term "comprises, comprising, including" or any other variation thereof is intended to cover non-exclusive inclusion, so that the process, method, article, or device including the list of elements does not only include those elements, but may include other elements that are not explicitly listed or inherent to such process, method, article, or device. Elements starting with "a, an", etc. do not exclude the presence of additional identical components in the process, method, article, or device including the component without more constraints. Moreover, the term "another" is defined as at least the second or more. As used herein, the terms "including", "having" are defined as "comprising". Furthermore, the background section is not admitted to be prior art, but rather is written as the inventor's own understanding of the background of some embodiments at the time of filing, and includes the inventor's own recognition of any problems accompanying the prior art and / or problems experienced in the inventor's own work.

Claims

1. A transducer assembly, comprising: base; A stress isolation support, the stress isolation support being placed on the base; A micro-electro-mechanical system die, wherein the micro-electro-mechanical system die is disposed on the stress isolation support; as well as A die attach adhesive is disposed between the MEMS die and the base, the die attach adhesive bonds the MEMS die to the base, and the stress isolation support is embedded in the die attach adhesive between the base and the MEMS die.

2. The transducer assembly according to claim 1, wherein: The stress isolation support has an elastic modulus of less than 100 MPa at room temperature.

3. The transducer assembly according to claim 1, wherein: The stress isolation standoffs include a plurality of stress isolation standoffs disposed between the micro-electro-mechanical system die and the base.

4. The transducer assembly according to claim 3, wherein: The plurality of stress isolation standoffs includes at least three struts.

5. The transducer assembly according to claim 1, wherein: The stress isolation standoff includes a rectangular shape deposited on the base.

6. The transducer assembly according to claim 1, wherein: The MEMS die is bonded to the base via a die attach adhesive formed in a rectangular shape.

7. The transducer assembly according to claim 1, wherein: The transducer assembly further comprises: A housing, the housing being disposed on the base and surrounding the MEMS die between the housing and the base; an external device interface disposed on the base; and An integrated circuit is electrically coupled to the microelectromechanical system die and to contacts of the external device interface, wherein the integrated circuit receives electrical signals from the microelectromechanical system die and communicates with a host device via the contacts of the external device interface.

8. The transducer assembly according to claim 7, wherein: in, The base includes an acoustic port, wherein the micro-electromechanical system die is acoustically coupled to the acoustic port, Wherein, the stress isolation support comprises at least one stress isolation support, and Wherein the die attach adhesive at least partially surrounds the acoustic port.

9. The transducer assembly according to claim 1, wherein: The micro-electromechanical system die comprises: a micro-electro-mechanical system die substrate coupled to the base via the stress isolation standoff and the die attach adhesive; a backplate coupled to the MEMS die substrate; and A diaphragm is connected to the micro-electromechanical system die substrate, and the diaphragm is movably arranged relative to the back plate.

10. The transducer assembly of claim 1, wherein: The plane of the stress isolation support adjusts the bottom plane of the MEMS die to be parallel to the surface of the base.

11. A method for manufacturing a micro-electromechanical system microphone assembly, the method comprising the following steps: Disposing a stress isolation standoff on a first surface of a base, wherein a micro-electromechanical system die is to be arranged in the first surface of the base, the first surface being opposite to a second surface of the base; depositing a die attach adhesive on the base including the area where the stress isolation standoff is disposed; and The MEMS die is placed onto the die attach adhesive and the stress isolation standoff, wherein the die attach adhesive bonds the MEMS die to the base and the stress isolation standoff is disposed between the MEMS die and the first surface of the base.

12. The method according to claim 11, in, The MEMS die includes a contact area contacting the die attach adhesive, and The step of providing the stress isolation support comprises: creating the stress isolation support in a pattern that at least partially matches the contact area of ​​the micro-electromechanical system die.

13. The method according to claim 11, wherein: The method further includes the step of forming an external device interface having electrical contacts on the second surface of the base.

14. The method according to claim 11, wherein: The step of providing the stress isolation support comprises any one of the following items: screen printing, spraying or needle dispensing the stress isolation support on the first surface of the base.

15. The method according to claim 11, wherein: The stress isolation standoff includes a plurality of stress isolation standoffs disposed between the micro-electromechanical system die substrate and the base.

16. The method according to claim 11, wherein: The stress isolation standoff includes a rectangular shape deposited on the base.

17. The method according to claim 11, in, The step of depositing the die attach adhesive comprises depositing the die attach adhesive in a rectangular shape on the base, and The MEMS die is bonded to the base via the die bonding adhesive in a rectangular shape.

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