The present disclosure relates to a micro speaker, and, in particular, to a package structure of a micro speaker including a membrane having a straight edge and a vent hole.
Since electronic products are being developed to be smaller and thinner, how to scale down the size of these electronic products is an important topic. The micro electromechanical system (MEMS) technique is a technique for effectively scaling down the size of elements. The concept of the MEMS technique is to combine semiconductor process techniques and precision micromachining techniques, and to manufacture micro elements and micro systems with multiple functions. However, there is still room for improvement of micro speakers using the MEMS technique.
An embodiment of the present invention provides a package structure of a micro speaker, which includes a substrate, a membrane, a coil, and a magnetic element. The substrate has a hollow chamber. The membrane is disposed on the substrate and covers the hollow chamber. The coil is embedded in the membrane. The magnetic element is disposed in the hollow chamber. A vent hole is formed in and penetrates the membrane, and the vent hole is separated from the coil and communicates with the hollow chamber.
An embodiment of the present disclosure provides package structure of a micro speaker, which includes a substrate, a membrane, a coil, and a magnetic element. The substrate has a hollow chamber. The membrane is disposed on the substrate and covers the hollow chamber. The membrane has at least one straight edge. The coil is embedded in the membrane. In addition, the magnetic element is disposed in the hollow chamber.
In addition, an embodiment of the present disclosure provides package structure of a micro speaker, which includes a substrate, a membrane, a coil, and a magnetic element. The substrate has a hollow chamber. The membrane is disposed on the substrate and covers the hollow chamber. The membrane has at least one straight edge. The coil is embedded in the membrane. In addition, the magnetic element is disposed in the hollow chamber. A vent hole is formed in and penetrates the membrane, and the vent hole is separated from the coil and communicates with the hollow chamber.
The present disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The package structures of the micro speaker of some embodiments of the present disclosure are described in the following description. However, it should be appreciated that the following detailed description of some embodiments of the disclosure provides various concepts of the present disclosure which may be performed in specific backgrounds that can vary widely. The specific embodiments disclosed are provided merely to clearly describe the usage of the present disclosure by some specific methods without limiting the scope of the present disclosure.
Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should be appreciated that, in each case, the term, which is defined in a commonly used dictionary, should be interpreted as having a meaning that conforms to the relative skills of the present disclosure and the background or the context of the present disclosure, and should not be interpreted in an idealized or overly formal manner unless so defined in the present disclosure.
In some embodiments, the membrane 110 has at least straight edge. For example, the membrane 110 may be shaped like a rectangle, a rounded rectangle, a polygon, a rounded polygon, or another regular or irregular shape, when viewed from a top view. More specifically, the membrane 110 has a plurality of edges 111 and a plurality of corners 112, and each of the corners 112 is connected between two adjacent edges 111. Accordingly, compared to a conventional circular membrane, the membrane 110 may have more surface area under the same chip size, and therefore may achieve a higher sound pressure level and better performance (for example, higher sensitivity) than the conventional design.
In addition, at least one vent hole 113 is formed in and penetrates the membrane 110. The vent hole 113 is shown to penetrate the membrane 110 in the normal direction of the substrate 100. However, other directions are also possible and included within the scope of the present disclosure. In some embodiments, the vent hole 113 is separated from the multi-layered coil 120 in a top view. As a result, the vent hole 113 may not make negative impact to the operation of the multi-layered coil 120. The vent hole 113 may connect the front side of the membrane 110 and the back side of the membrane 110, and therefore the pressure of two sides is balanced via the vent hole 113. Therefore, better user experience may be provided, and the reliability of the speaker may also be increased. For example, the vent hole 113 may reduce the defect (such as leakage, which may be referred to as “roll-off”) occurred in the low frequency range. In some embodiments, the diameter of the vent hole 113 is between about 1 μm and about 100 μm. However, the present disclosure is not limited thereto. In some embodiments, the vent hole 113 may have non-circular shape, and the length and/or width of the vent hole 113 is between about 1 μm and about 100 μm.
The multi-layered coil 120 is embedded in the membrane 110. That is, the multi-layered coil 120 is not actually exposed from the top surface of the membrane 110 in the top view. For the purpose of illustration, the multi-layered coil 120 is shown in the present disclosure. The multi-layered coil 120 is configured to transmit electrical signals and drive the membrane 110 to deform relative to the substrate 100 according to the electrical signals.
In some embodiments, the multi-layered coil 120 includes a first metal layer 121 and a second metal layer 122. The first metal layer 121 is electrically connected to the second metal layer 122 in an opening 110E of the membrane 110 to transmit electrical signals and control the operation of the package structure 10 of the micro speaker. In some embodiments, the first metal layer 121 includes a spiral structure 121A located in the center of the membrane 110 and a wavy structure 121B extending from the spiral structure 121A to the periphery of the membrane 110. The spiral structure 121A surrounds the central axis O of the membrane 110, and the wavy structure 121B connects the spiral structure 121A to the opening 110E. By providing the wavy structure 121B, the membrane 110 can be more flexible and the difficulty of vibration can be reduced.
In some embodiments, a dielectric layer 130 is disposed between the first metal layer 121 and the second metal layer 122 to prevent a short circuit between the first metal layer 121 and the second metal layer 122. A via hole 132 is formed in the dielectric layer 130. The second metal layer 122 crosses the spiral structure 121A and is electrically connected to the first metal layer 121 through the via hole 132. The process of manufacturing the package structure 10 is described in detail below in conjunction with
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In some embodiments, the dielectric layer 115A may be silicon dioxide (SiO2) or other oxides or nitrides that can be used as a dielectric layer. The dielectric layer 115A may be formed on the substrate 100 through thermal oxidation, chemical vapor deposition (CVD), low pressure CVD (LPCVD), atmospheric pressure CVD (APCVD), plasma-enhanced chemical vapor deposition (PECVD), or a combination thereof.
In some embodiments, the dielectric layer 115B may be silicon dioxide (SiO2) or other oxides or nitrides that can be used as a dielectric layer. The dielectric layer 115B may be formed on the dielectric layer 115A through thermal oxidation, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), or a combination thereof. It is noted that although two dielectric layers 115A and 115B are shown in the present embodiments, less or more dielectric layers may be provided in other embodiments, and these configurations are within the scope of the present disclosure.
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In some embodiments, the first metal layer 121 may include aluminum silicon, aluminum, copper, or a combination thereof. In some embodiments, the width of the first metal layer 121 may be between about 1 μm and about 500 μm, and the thickness of the first metal layer 121 may be between about 0.1 μm and about 20 μm. However, the present disclosure is not limited thereto.
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In some embodiments, the second metal layer 122 may include aluminum silicon, aluminum, copper, or a combination thereof. In some embodiments, the width of the second metal layer 122 may be between about 1 μm and about 500 μm, and the thickness of the second metal layer 122 may be between about 0.1 μm and about 20 μm. However, the present disclosure is not limited thereto.
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In some embodiments, the vent hole 113 is formed and communicates with the hollow chamber 150 during the formation of the scribe line 140. That is, the vent hole 113 may formed along with the scribe line 140. In some embodiments, the vent hole 113 may be formed during some other etching process. such as a singulation process, etc. Accordingly, additional process is not required for forming the vent hole 113, reducing the time and cost of manufacturing the package 10 of the speaker.
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A plurality of vent holes 113 are formed in and penetrates the membrane 110. In some embodiments, the vent holes 113 are separated from the multi-layered coil 120 and arranged along the profile of the membrane 110 in a top view. The vent holes 113 may connect the front side of the membrane 110 and the back side of the membrane 110, and therefore the pressure of the two sides is balanced via the vent holes 113. Furthermore, multiple vent holes 113 may help to decrease the stiffness of the membrane 110, improving the sensitivity of the membrane 110, which relates to the performance (such as sound pressure level) of the micro speaker. In some other embodiments, the vent holes 113 may be arranged in the membrane 110 irregularly, and any possible arrangement of the vent holes 113 is included within the scope of the present disclosure.
A plurality of vent holes 114 are formed in and penetrates the membrane 110. In some embodiments, the vent holes 114 are separated from the multi-layered coil 120 and arranged along the profile of the membrane 110 in a top view. The vent holes 114 may connect the front side of the membrane 110 and the back side of the membrane 110, and therefore the pressure of the two sides is balanced via the vent holes 114. In some embodiments, each of the vent holes 114 has an elongated shape, and therefore the vent holes 114 may be referred to as “vent slots” sometimes. Similarly, these vent holes 114 may help to decrease the stiffness of the membrane 110, improving the sensitivity of the membrane 110, which relates to the performance (such as sound pressure level) of the micro speaker. In some other embodiments, the elongated vent holes 114 may be arranged along with the circular vent holes 113 in the membrane 110 arbitrarily, and any possible arrangement of the vent holes 113 and 114 is included within the scope of the present disclosure.
A vent hole 116 is formed in and penetrates the membrane 110. In some embodiments, the vent hole 116 is separated from the multi-layered coil 120 in a top view. The vent hole 116 may connect the front side of the membrane 110 and the back side of the membrane 110, and therefore the pressure of the two sides is balanced via the vent hole 116.
In some embodiments, the vent hole 116 has a bow profile in the top view and divides the membrane 110 into a main body 110M and a vent portion 110A that is connected to the main body 110M. When the pressures are different on opposite sides of the membrane 110, airflow may pass through the vent hole 116 and push the vent portion 110A to move relative to the main body 110M, and the pressures may be balanced more rapidly. Otherwise, when the pressures are substantially the same on opposite sides of the membrane 110, the vent portion 110A may be substantially coplanar with the main body 110M. As such, the effective surface area of the membrane 110 may be obtained (including the vent portion 110A) for higher sensitivity.
Therefore, the vent hole 116 may be referred to as “dynamic vent hole” sometimes. Similarly, the vent hole 116 may help to decrease the stiffness of the membrane 110, improving the sensitivity of the membrane 110, which relates to the performance (such as sound pressure level) of the micro speaker. It is noted that although one vent hole 116 is shown in the present embodiments, more vent hole 116 may be provided regularly or irregularly in other embodiments, and these configurations are within the scope of the present disclosure.
A vent hole 117 is formed in and penetrates the membrane 110. In some embodiments, the vent hole 117 is separated from the multi-layered coil 120 in a top view. The vent hole 117 may connect the front side of the membrane 110 and the back side of the membrane 110, and therefore the pressure of the two sides is balanced via the vent hole 117.
In some embodiments, the vent hole 117 has a bow portion 117A and a linear portion 117B that is connected to the bow portion 117B. Correspondingly, the membrane 110 is divided into a main body 110M, a round portion 110A, and a linear portion 110B. The round portion 110A is connected to the main body 110M via the linear portion 110B. When the pressures are different on opposite sides of the membrane 110, airflow may pass through the vent hole 117 and push the round portion 110A and the linear portion 110B to move relative to the main body 110M, and the pressures may be balanced more rapidly. As such, the round portion 110A and the linear portion 110B may be referred to as “vent portion” for equalizing the pressure on opposite sides of the membrane 110. Otherwise, when the pressures are substantially the same on opposite sides of the membrane 110, the round portion 110A and the linear portion 110B may be substantially coplanar with the main body 110M. As such, the effective surface area of the membrane 110 may be obtained for higher sensitivity.
As described above, some embodiments of the present disclosure provide a package structure of a micro speaker including a membrane having a straight edge and/or a vent hole. In some embodiments, compared to conventional circular membrane, the disclosed membrane (such as having a shape of rounded rectangle) may have greater surface area under the same chip size, and therefore higher sound pressure level and better performance (for example, higher sensitivity) may be achieved. In addition, one or more vent hole are formed in the membrane for equalizing pressures of opposite sides of the membrane. Therefore, better user experience may be provided, and the reliability of the speaker may also be increased.
While the embodiments and the advantages of the present disclosure have been described above, it should be understood that those skilled in the art may make various changes, substitutions, and alterations to the present disclosure without departing from the spirit and scope of the present disclosure. In addition, the scope of the present disclosure is not limited to the processes, machines, manufacture, composition, devices, methods and steps in the specific embodiments described in the specification. Those skilled in the art may understand existing or developing processes, manufacture, compositions, devices, methods and steps from some embodiments of the present disclosure. As long as those may perform substantially the same function in the aforementioned embodiments and obtain substantially the same result, they may be used in accordance with some embodiments of the present disclosure. Therefore, the scope of the present disclosure includes the aforementioned processes, manufacture, composition, devices, methods, and steps. Furthermore, each of the appended claims constructs an individual embodiment, and the scope of the present disclosure also includes every combination of the appended claims and embodiments.