MEMS device and method for manufacturing the same

Abstract

A microelectromechanical device (MEMS) and a method for manufacturing the same are provided. The MEMS includes a substrate, a polymer film on the substrate, a cavity penetrating the substrate, and a plurality of coil structures on the substrate and in the polymer film. The polymer film has a lower surface facing the substrate. The polymer film includes a corrugated pattern disposed on the lower surface. A portion of the polymer film is exposed in the cavity.

Description

Technical Field

[0001] This invention relates to microelectromechanical systems (MEMS) devices and methods for manufacturing them, and particularly to microelectromechanical devices having corrugated patterns and methods for manufacturing them. Prior Technology

[0002] Microelectromechanical components (MEMS) are miniature devices created by combining electronic technology and mechanical engineering. They typically incorporate sensing, processing, and / or actuation functions. MEMS are widely used in consumer electronics. For example, in loudspeakers, the application of MEMS allows for smaller size, lower power consumption, and higher reliability, making MEMS loudspeakers a focus of market attention. However, the performance of existing MEMS loudspeakers remains insufficient.

[0003] Therefore, there is a need to propose an improved microelectromechanical loudspeaker with good performance. Summary of the Invention

[0004] According to one embodiment, a microelectromechanical device (MEMS) is provided. The MEMS includes a substrate, a polymer film on the substrate, a cavity penetrating the substrate, and a plurality of coil structures on the substrate and in the polymer film. The polymer film has a lower surface facing the substrate. The polymer film includes a corrugated pattern disposed on the lower surface. A portion of the polymer film is exposed in the cavity.

[0005] According to one embodiment, a method for manufacturing a microelectromechanical device (MEMS) is provided. The method includes the following steps: providing a substrate; forming a plurality of coil structures on the substrate; forming a dielectric layer on the substrate and the plurality of coil structures; removing a first portion of the dielectric layer to form a sacrificial corrugation pattern adjacent to the plurality of coil structures; and forming a polymer film on the dielectric layer, wherein the polymer film covers the sacrificial corrugation pattern of the dielectric layer.

[0006] To provide a better understanding of the above and other aspects of the present invention, specific embodiments are described below in conjunction with the accompanying drawings. Simple Explanation of the Diagram

[0007] Figure 1 is a cross-sectional view illustrating a microelectromechanical device according to an embodiment of the present invention; and Figures 2-12 are exemplary illustrations of a method for manufacturing a microelectromechanical device according to one embodiment of the present invention. Implementation

[0008] The following are related embodiments, illustrated in conjunction with figures, to illustrate in detail the microelectromechanical device and its manufacturing method disclosed herein. However, this disclosure is not limited thereto. The descriptions in the embodiments, such as detailed structures, manufacturing steps, and material applications, are merely illustrative, and the scope of protection intended by this disclosure is not limited to the described embodiments.

[0009] It should be noted that this disclosure does not show all possible embodiments. Those skilled in the art can make changes and modifications to the structure and manufacturing methods of the embodiments without departing from the spirit and scope of this disclosure to meet the needs of practical applications. Therefore, other embodiments not presented in this disclosure may also be applied. Furthermore, the drawings are simplified to clearly illustrate the embodiments, and the dimensions in the drawings are not drawn to scale according to the actual product. Therefore, the specification and drawings are only for describing the embodiments and are not intended to limit the scope of protection of this disclosure. The same or similar element symbols are used to represent the same or similar elements.

[0010] Please refer to Figure 1. Figure 1 is a cross-sectional view illustrating a microelectromechanical device 10 according to one embodiment of the present invention. The microelectromechanical device 10 may be, for example, a microelectromechanical loudspeaker. The microelectromechanical device 10 includes a substrate 101, an oxide layer 102, a first dielectric layer 103, a second dielectric layer 104, a third dielectric layer 105, a polymer film 106, a plurality of coil structures 110-117, a metal layer 109, and a cavity C. The oxide layer 102 and the first dielectric layer 103 may contain different materials.

[0011] An oxide layer 102, a first dielectric layer 103, and a polymer film 106 may be disposed on a substrate 101 along a longitudinal direction. The longitudinal direction may, for example, be the normal direction of the upper surface of the substrate 101. The oxide layer 102 is between the first dielectric layer 103 and the substrate 101. The first dielectric layer 103 is between the polymer film 106 and the substrate 101. Coil structures 110-114 are on the substrate 101 and on the first dielectric layer 103. Coil structures 110-114 may be within the polymer film 106. A second dielectric layer 104 is on the first dielectric layer 103. A portion of the second dielectric layer 104 may be on the sidewalls of coil structures 110-114. A portion of the second dielectric layer 104 may cover the upper surface of coil structure 111. A portion of the second dielectric layer 104 may partially cover the upper surfaces of coil structures 110 and 112. A coil structure 115 is on coil structure 110 and the second dielectric layer 104. Coil structure 116 is on coil structure 111 and the second dielectric layer 104. Coil structure 117 is on coil structure 112 and the second dielectric layer 104. Coil structures 115-117 may be in the polymer film 106. A third dielectric layer 105 is on the first dielectric layer 103. A portion of the third dielectric layer 105 may be on the sidewalls of coil structures 115-117. A portion of the third dielectric layer 105 may cover the upper surfaces of coil structures 116 and 117. A portion of the third dielectric layer 105 may partially cover the upper surface of coil structure 115. A metal layer 109 is between the substrate 101 and the polymer film 106. The metal layer 109 may be in the first dielectric layer 103. Coil structures 110-117 may be coupled to a control circuit (not shown), which can control the current flowing through coil structures 110-117.

[0012] A polymer film 106 is vibratoryly disposed on a substrate 101. The polymer film 106 can vibrate up and down, for example, along a longitudinal direction. The polymer film 106 can change its vibration mode according to the magnitude and direction of the current flowing through the coil structures 110-117. The polymer film 106 has an upper surface 106S1 and a lower surface 106S2 opposite to the upper surface 106S1. The lower surface 106S2 of the polymer film 106 faces the substrate 101. The polymer film 106 includes a corrugated pattern 108 disposed on the lower surface 106S2. The corrugated pattern 108 has a plurality of protrusions 1081 and a plurality of recesses 1082. In this embodiment, the plurality of protrusions 1081 are separated from each other, the plurality of recesses 1082 are separated from each other, and the plurality of protrusions 1081 and the plurality of recesses 1082 are alternately arranged. The protrusions 1081 can protrude toward the cavity C. The upper surface 106S1 of the polymer film 106 may include a flat surface region 118 that overlaps the corrugated pattern 108 in the longitudinal direction. The flat surface region 118 may be, for example, a smooth surface or a surface parallel to a transverse direction. The transverse direction is perpendicular to the longitudinal direction. The corrugated pattern 108 may not overlap the coil structures 110-117 in the longitudinal direction. In one embodiment, the corrugated pattern 108 may surround the coil structures 110-117. For example, the corrugated pattern 108 may be arranged in a circular, rectangular, or other shape and may be disposed around the periphery of multiple coil structures. The polymer film 106 may also include a hole 931, the bottom of which may expose the coil structure 115, and the sidewalls of which may expose the third electrical layer 105 to the polymer film 106.

[0013] Cavity C penetrates the substrate 101, oxide layer 102, and first dielectric layer 103. Cavity C may include a first cavity portion C1 and a second cavity portion C2 that are interconnected. The first cavity portion C1 penetrates the substrate 101 and oxide layer 102. The second cavity portion C2 penetrates the first dielectric layer 103. The sidewalls of the substrate 101 and the sidewalls of the oxide layer 102 are exposed in the first cavity portion C1 of cavity C. A portion of the first dielectric layer 103 and a portion of the metal layer 109 are exposed in the first cavity portion C1 of cavity C. The first dielectric layer 103 has a lower surface 103S2 facing the substrate 101, and a portion of the lower surface 103S2 of the first dielectric layer 103 is exposed in the first cavity portion C1 of cavity C. The metal layer 109 has a lower surface 109S2 facing the substrate 101, and a portion of the lower surface 109S2 of the metal layer 109 is exposed in the first cavity portion C1 of cavity C. A portion of the polymer film 106 may be exposed in the second cavity portion C2 of the cavity C. The corrugated pattern 108 of the polymer film 106 may be exposed in the second cavity portion C2 of the cavity C. The sidewalls of the first dielectric layer 103 and the sidewalls of the metal layer 109 may be exposed in the second cavity portion C2 of the cavity C. The widths of the first cavity portion C1 and the second cavity portion C2 in the lateral direction may be different from each other. For example, the width of the first cavity portion C1 in the lateral direction may be greater than the width of the second cavity portion C2 in the lateral direction.

[0014] The microelectromechanical device 10 may also include a slit 1032. The slit 1032 may extend in a longitudinal direction, the bottom of the slit 1032 may expose the substrate 101, and the sidewalls of the slit 1032 may expose the oxide layer 102, the first dielectric layer 103, and the polymer film 106.

[0015] Figures 2-12 illustrate, by way of manufacturing a semiconductor component according to one embodiment of the present invention.

[0016] Please refer to Figure 2. A substrate 101A is provided. An oxide layer 102A is formed on the substrate 101A. In one embodiment, a portion of the substrate 101A can be oxidized to form the oxide layer 102A by thermal oxidation. In another embodiment, the oxide layer 102A can be formed on the substrate 101A by deposition processing such as chemical vapor deposition. The substrate 101A may contain a semiconductor material, such as silicon. The oxide layer 102A may contain an oxidized semiconductor material, such as silicon oxide. In one embodiment, the thickness H1 of the oxide layer 102A in the longitudinal direction may be approximately 4 mm. .

[0017] Please refer to Figure 3. A metal layer 109 and a first dielectric layer 103A are formed. The metal layer 109 can serve as an etch stop layer in subsequent steps. Figure 3 illustrates the metal layer 109 as discontinuous in the lateral direction, but this disclosure is not limited thereto, and the metal layer 109 may also be continuous in the lateral direction. In one embodiment, the metal layer 109 can be formed on the oxide layer 102A by sputtering or other deposition processes, followed by the formation of the first dielectric layer 103A on the metal layer 109 by chemical vapor deposition or other deposition processes. The metal layer 109 may comprise aluminum or other suitable metallic materials. The first dielectric layer 103A may comprise a dielectric material, such as PE-TEOS (plasma enhanced tetraethyl orthosilicate). In one embodiment, the thickness H2 of the metal layer 109 in the longitudinal direction may be approximately 1 mm. The thickness H3 of the first dielectric layer 103A in the longitudinal direction can be approximately 6. .

[0018] Please refer to Figures 4-5. Coil structures 110-114 and a second dielectric layer 104A are formed on a first dielectric layer 103A. The second dielectric layer 104A may at least partially cover the coil structures 110-114. In one embodiment, the coil structures 110-114 may be formed on the first dielectric layer 103A by sputtering or other deposition processes. Then, the second dielectric layer 104A may be formed on the first dielectric layer 103A by a deposition process such as chemical vapor deposition. Subsequently, wet etching, dry etching, or other suitable methods may be performed to remove portions of the second dielectric layer 104A, forming holes 531 and 532. Holes 531 and 532 expose portions of the upper surfaces of coil structures 110 and 112, respectively. Coil structures 110-114 may contain a conductive material, such as aluminum or tungsten. The second dielectric layer 104A may contain a dielectric material, such as PE-TEOS. In one embodiment, the height H4 of each coil structure 110-114 in the longitudinal direction can be approximately 20 mm. The thickness H5 of the second dielectric layer 104A in the longitudinal direction can be approximately 3. .

[0019] Please refer to Figure 6. Coil structures 115-117 are formed on the second dielectric layer 104A. Coil structure 115 may be located on coil structure 110. Coil structure 116 may be located on coil structure 111. Coil structure 117 may be located on coil structure 112. Coil structure 115 may have a recess 631, which at least partially overlaps with hole 531 in the longitudinal direction. Coil structure 117 may have a recess 632, which at least partially overlaps with hole 532 in the longitudinal direction. In one embodiment, coil structures 115-117 may be formed on the second dielectric layer 104A by sputtering or other deposition processes. Coil structures 115-117 may contain a conductive material, such as aluminum or tungsten. In one embodiment, the height H6 of each coil structure 115-117 in the longitudinal direction may be approximately 10 mm. .

[0020] Please refer to Figure 7. A first portion of the second dielectric layer 104A is removed to form a sacrificial corrugation pattern 770 adjacent to the coil structures 113-114. This step may also include removing a second portion of the second dielectric layer 104A (e.g., the portion located on the upper surfaces of coil structures 113 and 114) to expose the upper surfaces of coil structures 113 and 114, and removing a third portion of the second dielectric layer 104A (e.g., the portion between coil structures 110 and 114) to expose a portion of the upper surface of the first dielectric layer 103A. The remaining second dielectric layer 104A may be defined as the second dielectric layer 104B. In one embodiment, the first, second, and third portions of the second dielectric layer 104A may be removed by wet etching, dry etching, or other suitable methods.

[0021] Please refer to Figure 8. A third dielectric layer 105A is formed on the first dielectric layer 103A. A sacrificial corrugation pattern 870 is formed on the sacrificial corrugation pattern 770. The third dielectric layer 105A may cover coil structures 113, 114, 116, and 117. The third dielectric layer 105A may cover a portion of coil structure 115. The aperture 831 in the third dielectric layer 105A may expose a portion of the upper surface of coil structure 115. In one embodiment, a third dielectric layer can be formed on the structure of Figure 7 by a deposition process such as chemical vapor deposition. This third dielectric layer can cover the first dielectric layer 103A, coil structures 113-117, and the second dielectric layer 104B containing the sacrificial corrugation pattern 770. Then, a wet etching process, dry etching process, or other suitable method can be performed to remove a first portion of the third dielectric layer to form a sacrificial corrugation pattern 870 on the sacrificial corrugation pattern 770. A second portion of the third dielectric layer (e.g., the portion located on the upper surface of coil structure 115) is removed to form a hole 831 and expose the upper surface of coil structure 115. A third portion of the third dielectric layer (e.g., the portion between coil structure 115 and coil structure 116, between coil structure 117 and coil structure 113, and between coil structure 113 and coil structure 114) is removed to expose a portion of the upper surface of the first dielectric layer 103A. The remaining third dielectric layer can be defined as the third dielectric layer 105A. The third dielectric layer 105A may comprise a dielectric material, such as PE-TEOS. In one embodiment, the thickness H7 of the third dielectric layer 105A in the longitudinal direction may be approximately 10. .

[0022] Please refer to Figure 9. A polymer film 106A is formed. The polymer film 106A may cover the first dielectric layer 103A, the third dielectric layer 105A, the sacrificial corrugation pattern 770, and the sacrificial corrugation pattern 870. The polymer film 106A may directly contact the sacrificial corrugation pattern 770 and the sacrificial corrugation pattern 870. The polymer film 106A may directly contact the first dielectric layer 103A. The polymer film 106A may contain holes 931 that expose the coil structure 115. In one embodiment, the polymer film 106A may be formed on the third dielectric layer 105A by coating, followed by wet etching, dry etching, or other suitable methods to form holes 931 in the polymer film 106A. The polymer film 106A may contain a polymer, such as polyimide. In one embodiment, the thickness H8 of the polymer film 106A in the longitudinal direction may be approximately 30 mm. .

[0023] Please refer to Figure 10. A slit 1032 is formed. In one embodiment, a portion of the polymer film 106A, a portion of the first dielectric layer 103A, and a portion of the oxide layer 102A may be removed by wet etching, dry etching, or other suitable methods to form the slit 1032. The remaining polymer film 106A may be defined as polymer film 106. The remaining first dielectric layer 103A may be defined as first dielectric layer 103B. The remaining oxide layer 102A may be defined as oxide layer 102B.

[0024] Please refer to Figure 11. A chamber 101V is formed. Chamber 101V exposes the oxide layer 102C and the substrate 101. In one embodiment, the structure of Figure 10 can be subjected to wet etching, dry etching, or other suitable methods. The etching process may, for example, stop in the oxide layer 102B of Figure 10, thereby removing a portion of the substrate 101A and a portion of the oxide layer 102B to form the chamber 101V. The remaining substrate 101A can be defined as substrate 101. The remaining oxide layer 102B can be defined as oxide layer 102C.

[0025] Please refer to Figure 12. A corrugated pattern 108 is formed. In one embodiment, the structure of Figure 11 may be subjected to wet etching, dry etching, or other suitable methods to remove a portion of the oxide layer 102C, a portion of the first dielectric layer 103B, a portion of the second dielectric layer 104B, and a portion of the third dielectric layer 105A of Figure 11 to form a corrugated pattern 108 in the polymer film 106. In this step, the removed portion of the second dielectric layer 104B contains a sacrificial corrugated pattern 770; the removed portion of the third dielectric layer 105A contains a sacrificial corrugated pattern 870. The remaining oxide layer 102C may be defined as oxide layer 102. The remaining first dielectric layer 103B may be defined as first dielectric layer 103. The remaining second dielectric layer 104B may be defined as second dielectric layer 104. The remaining third dielectric layer 105A may be defined as third dielectric layer 105. A corrugated pattern 108 is formed on the lower surface 106S2 of the polymer film 106, which faces the substrate 101. The corrugated pattern 108 may have a shape complementary to the sacrificial corrugated patterns 770 and 870. For example, the corrugated pattern 108 may have a plurality of protrusions 1081 and a plurality of recesses 1082, the shape of which may be complementary to the shape of the sacrificial corrugated patterns 770 and 870; that is, if the sacrificial corrugated patterns 770 and 870 have an arc shape, the recesses 1082 of the corrugated pattern 108 may have a corresponding concave arc shape. The depth of the recess 1082 in the longitudinal direction can be determined by the sum of the thicknesses of the sacrificial corrugated patterns 770 and 870 in the longitudinal direction. Therefore, the size of the corrugated pattern 870 can be changed by adjusting the thicknesses of the sacrificial corrugated patterns 770 and 870 in the longitudinal direction, thereby adjusting the thickness of the polymer film 106 in the longitudinal direction. In one embodiment, the depth of the recess 1082 in the longitudinal direction can be approximately equal to the sum of the thicknesses of the sacrificial corrugated patterns 770 and 870 in the longitudinal direction.

[0026] In one embodiment, the microelectromechanical device 10 shown in Figure 1 can be obtained by performing the steps illustrated in Figures 2-12.

[0027] According to the above embodiments, the microelectromechanical device and its manufacturing method disclosed herein include a polymer film disposed on a substrate, and the polymer film includes a corrugated pattern on its lower surface. The corrugated pattern can change the thickness of the polymer film, thereby solving or improving the problem of insufficient sensitivity caused by an excessively thick polymer film, and effectively improving the sensitivity and performance of the microelectromechanical speaker. In addition, the corrugated pattern can ensure that the thickness of the polymer film is maintained within an appropriate range, thereby avoiding the problem of insufficient strength caused by an excessively thin polymer film. Moreover, the corrugated pattern of this disclosure is located on the lower surface of the polymer film. Compared with the comparative example where the corrugated pattern is designed on the upper surface of the polymer film, the configuration of this disclosure does not require a patterning process to form a corrugated pattern on the polymer film, thereby avoiding damage to the polymer film caused by removing photoresist during the patterning process and avoiding the problem of photoresist residue on the polymer film causing contour changes. Furthermore, it can reduce the number of photomasks used in the process, which has the effect of simplifying the process and improving yield.

[0028] It should be noted that the diagrams, structures, and steps described above are for illustrating some embodiments or applications of this disclosure, and this disclosure is not limited to the scope and application of the above structures and steps. Other embodiments with different structural forms, such as known components with different internal parts, can be applied, and the illustrative structures and steps can be adjusted according to the needs of actual applications. Therefore, the structures in the diagrams are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art will understand that the application of the related structures and steps of this disclosure, such as the arrangement or configuration of related components and layers in a microelectromechanical device, or the details of manufacturing steps, may be subject to corresponding adjustments and variations depending on the requirements of the actual application.

[0029] In summary, although the present invention has been disclosed above through the use of embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and alterations may be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0030] 10: Microelectromechanical devices 101,101A:Substrate 101V: Chamber 102, 102A, 102B: Oxide layers 103, 103A, 103B: First dielectric layer 104, 104A, 104B: Second dielectric layer 105, 105A: Third dielectric layer 106, 106A: Polymer film 106S1: Upper surface 10³S², 10⁶S², 10⁹S²: Lower surface 108: Ripple Pattern 109: Metal layer 110, 111, 112, 113, 114, 115, 116, 117: Coil Structure 118: Flat surface area 531, 532, 831, 931: Holes 631, 632: Depression 770, 870: Sacrificial ripple pattern 1032: Slit 1081:convex part 1082: concave part C: Cavity C1: First cavity C2: Second cavity H1~H3, H5, H7, H8: Thickness H4, H6: Height

Claims

1. A microelectromechanical device comprising: a substrate; a polymer film on the substrate, the polymer film having a lower surface facing the substrate, the polymer film including a corrugated pattern disposed on the lower surface; a cavity penetrating the substrate, a portion of the polymer film being exposed in the cavity; and a plurality of coil structures on the substrate and in the polymer film.

2. The microelectromechanical device as claimed in claim 1, wherein the corrugated pattern of the polymer film is exposed in the cavity.

3. The microelectromechanical device as claimed in claim 1, wherein the corrugated pattern of the polymer film includes a plurality of protrusions separated from each other, the protrusions projecting toward the cavity.

4. The microelectromechanical device as claimed in claim 1, wherein the polymer film has an upper surface relative to the lower surface, the upper surface of the polymer film including a flat surface region that overlaps the corrugated pattern in a longitudinal direction.

5. The microelectromechanical device as claimed in claim 1, further comprising a dielectric layer between the substrate and the polymer film, the cavity extending through the dielectric layer.

6. The microelectromechanical device as claimed in claim 5, wherein the dielectric layer has a lower surface facing the substrate, a portion of which is exposed in the cavity.

7. The microelectromechanical device as described in claim 5 further includes an oxide layer between the dielectric layer and the substrate.

8. The microelectromechanical device as claimed in claim 7, wherein the oxide layer and the dielectric layer comprise different materials.

9. The microelectromechanical device as claimed in claim 7, wherein the cavity penetrates the oxide layer.

10. The microelectromechanical device as claimed in claim 1, further comprising a metal layer between the substrate and the polymer film, a portion of the metal layer being exposed in the cavity.

11. A method for manufacturing a microelectromechanical device, comprising: providing a substrate; forming a plurality of coil structures on the substrate; forming a dielectric layer on the substrate and the coil structures; removing a first portion of the dielectric layer to form a sacrificial corrugation pattern adjacent to the coil structures; and forming a polymer film on the dielectric layer, wherein the polymer film covers the sacrificial corrugation pattern of the dielectric layer.

12. The method as described in claim 11 further comprises: removing a portion of the substrate and a portion of the dielectric layer to form a cavity that exposes a portion of the polymer film.

13. The method as described in claim 11 further comprises: forming another dielectric layer on the dielectric layer; and removing a portion of the other dielectric layer to form another sacrificial corrugation pattern on the sacrificial corrugation pattern, wherein the polymer film is in direct contact with the sacrificial corrugation pattern and the other sacrificial corrugation pattern.

14. The method of claim 13 further comprises: removing the sacrificial corrugation pattern of the dielectric layer and the other sacrificial corrugation pattern of the other dielectric layer to form a corrugation pattern in the polymer film, wherein the corrugation pattern is disposed on a lower surface of the polymer film, the lower surface of the polymer film facing the substrate, and the shape of the corrugation pattern is complementary to the sacrificial corrugation pattern and the other sacrificial corrugation pattern.

15. The method as described in claim 14 further comprises: removing a portion of the substrate to form a cavity in which the corrugated pattern is exposed.

16. The method as described in claim 15, wherein the corrugated pattern comprises a plurality of protrusions separated from each other, the protrusions projecting toward the cavity.

17. The method as claimed in claim 11, wherein the step of forming the sacrificial corrugation pattern includes removing a second portion of the dielectric layer formed on the upper surface of the coil structures.

18. The method as described in claim 11 further comprises: forming an oxide layer between the substrate and the polymer film.

19. The method as described in claim 18 further comprises: forming a metal layer between the oxide layer and the polymer film.

20. The method as described in claim 19 further comprises: removing a portion of the substrate, a portion of the oxide layer and a portion of the dielectric layer to form a cavity that exposes a portion of the metal layer and a portion of the polymer film.

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