MICROELECTROMECHANICAL SYSTEM DEVICE AND METHOD FOR MANUFACTURING THE SAME
A MEMS device includes a first structure including at least one first bump over a surface of the first structure, a second structure including a first side facing the surface of the first bump and a second side opposite to the first side, and a gap between the first structure and the second structure. The first structure and the second structure are configured to move in relation to each other. The first bump includes a plurality of first teeth over a stop surface of the first bump.
This patent claims the benefit of U.S. Provisional Patent Application Ser. No. 62/507,986 filed May 18, 2017, the entire disclosure of which is hereby incorporated by reference.
BACKGROUNDMicroelectromechanical Systems (MEMS) device is micro-sized device, normally in a range from less than 1 micron to several millimeters in size. The MEMS device includes mechanical elements (stationary element and/or movable element) to sense a physical condition such as force, acceleration, pressure, temperature or vibration, and electronic elements to process electrical signals. The MEMS devices are widely used in applications such as automotive system, inertial guidance systems, household appliances, protection systems for a variety of devices, and many other industrial, scientific, and engineering systems. Moreover, MEMS applications are extended to optical applications, such as movable mirrors, and radio frequency (RF) applications, such as RF switches.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of elements and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper”, “on” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
In the present disclosure, a device including a suspended movable portion and a bump is provided. The movable portion is suspended from e.g., a substrate with a space such as an air space. The bump is disposed adjacent to the movable portion to prevent the movable portion from being broken and/or adhered to the substrate or any structures overlying the substrate.
In the present disclosure, the device includes, but is not limited to, a Microelectromechanical Systems (MEMS) device, such as pressure sensor device, a microphone, a motion sensor device, an accelerometer device, or a gyroscope device. The suspended movable portion may include a proof mass, a vibrator, a diaphragm, an electrode, or any other movable structures.
As used herein, a “substrate” refers to a base material on which various layers and structures are formed. In some embodiments, the substrate includes a semiconductor substrate, such as a bulk semiconductor substrate. By way of example, the bulk semiconductor substrate includes an elementary semiconductor, such as silicon or germanium; a compound semiconductor, such as silicon germanium, silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, or indium arsenide; or combinations thereof. In some embodiments, the substrate includes a multilayered substrate, such as a silicon-on-insulator (SOI) substrate, which includes a bottom semiconductor layer, a buried oxide layer (BOX) and a top semiconductor layer. In still some embodiments, the substrate includes an insulative substrate, such as a glass substrate, a conductive substrate, or any other suitable substrate. In some embodiments, the substrate is a doped semiconductor substrate.
As used herein, “suspended” refers to a structure disposed above and spaced away from another structure, thereby allowing the structure moving in at least one direction with respective to another structure.
As used herein, a “movable portion” refers to a structure that is suspended formed over the substrate or some part of the substrate with a space therebetween. Accordingly, the movable portion is able to move or swing when experiencing a force, an acceleration, a deceleration, a vibration, an impact or the like. In some embodiments, the movable portion is conductive. In some embodiments, the movable portion is covered with a conductive layer. In some embodiments, the movable structure is not conductive.
As used herein, a “fixed portion” refers to a structure that is immobile with respect to the movable structure when experiencing a force, an acceleration, a deceleration, a vibration, an impact or the like. The stationary portion or the fixed portion may be formed directly or indirectly on the substrate, or is a part of the substrate. In some embodiments, the fixed portion is conductive. In some embodiments, the fixed structure is covered with a conductive layer. In some embodiments, the fixed structure is not conductive.
As used herein, a “bump” is a structure configured as a buffer to reduce damage in a collision and to avoid undesired adhesion. As used herein, a “stop surface” is a surface of an element that contacts another element.
As used herein, “teeth” refer recessed or protruded structures that make an uneven or a rough surface of the bump. As used herein, a “recess” is a structure recessed from a perimeter or an edge of another structure, and a “protrusion” is a structure protruded from a perimeter or an edge of another structure. The protrusion can be either formed of the same material as or different materials from the structure where the protrusion is protruded.
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The MEMS structure 200 includes one or more motion sensors or other MEMS elements, therefore is also referred to as MEMS substrate. In some embodiments of the present disclosure, the MEMS structure 200 includes a substrate including a fixed portion 202 and a movable portion 204 having motions sensors formed thereon. The movable portion 204 is able to move toward the capping structure 100 and/or the CMOS structure 300. In the present disclosure, the substrate includes a first side 200a facing the capping structure 100 and a second side 200b opposite to the first side 200a. In some embodiments of the present disclosure, the second side 200b faces the CMOS structure 300. The motion sensors or other MEMS elements can be formed over the movable portion 204 by various processes including etching, lithography, or other suitable process. In other words, the MEMS structure 200 includes the movable portion 204 moving in the gaps/cavities between the capping structure 100 and the CMOS structure 300 and serving as an element of the motion sensor or other MEMS elements. The movable portion 204 can be partially separated from the fixed portion 202 by through holes 206.
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In the present disclosure, the bump configured to constrain the movable portion of the MEMS structure includes the teeth. More important, the teeth over the stop surface of the bump or the teeth forming the stop surface of the bump make an uneven surface and thus contact area between the bump and the other structure is reduced. Accordingly, stiction is reduced.
In some embodiments, a MEMS device is provided. The MEMS device includes a first structure comprising at least one first bump over a surface of the first structure, a second structure comprising a first side facing the surface of the first bump and a second side opposite to the first side, and a gap between the first structure and the second structure. The first structure and the second structure are configured to move in relation to each other.
In some embodiments, a MEMS device is provided. The MEMS device includes a first structure including at least one first bump, a second structure bonded to the first structure, and a first gap between the first structure and the second structure. The first bump includes a plurality of first recesses being recessed from a stop surface of the first bump. The second structure includes a first side facing the surface of the first bump and a second side opposite to the first side.
In some embodiments, a method for manufacturing a MEMS device is provided. The method include providing a substrate, and forming at least one first bump over the substrate, and the first bump comprising a plurality of recesses being recessed from a surface of the first bump.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
Claims
1. A MEMS device comprising:
- a first structure comprising at least one first bump over a surface of the first structure, the first bump comprising a plurality of first teeth over a stop surface of the first bump;
- a second structure comprising a first side facing the surface of the first structure and a second side opposite to the first side; and
- a gap between the first structure and the second structure,
- wherein the first structure and the second structure are configured to move in relation to each other, the second structure comprises a movable portion being able to move toward the first structure, and the first bump faces the movable portion, the second structure further comprises a plurality of second bumps over the movable portion, and the second bumps respectively comprise a plurality of second teeth over a stop surface of the second bumps.
2. The MEMS device according to claim 1, wherein each of the first teeth comprises a front end surface forming the stop surface of the first bump.
3. (canceled)
4. (canceled)
5. (canceled)
6. The MEMS device according to claim 1, wherein each of the second teeth comprises a front end surface forming the stop surface of the second bump.
7. The MEMS device according to claim 1, wherein the plurality of second bumps are at the second side.
8. The MEMS device according to claim 1, wherein the first structure further comprises a third bump comprising a plurality of third teeth over a surface of the third bump.
9. The MEMS device according to claim 8, wherein the plurality of second bumps are at the first side.
10. The MEMS device according to claim 8, wherein the third teeth and the third bumps comprise different materials.
11. The MEMS device according to claim 8, wherein the first teeth and the third teeth comprise different materials.
12. A MEMS device comprising:
- a first structure comprising at least one first bump, the first bump comprising a plurality of first recesses being recessed from a stop surface of the first bump;
- a second structure bonded to the first structure, the second structure comprising a first side facing the first bump and a second side opposite to the first side; and
- a gap between the first structure and the second structure,
- wherein the first structure comprises a movable portion and the first bump is over the movable portion.
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. A method for manufacturing a MEMS device, comprising:
- providing a substrate;
- forming a patterned mask over the substrate;
- forming a patterned photoresist covering the patterned mask over the substrate;
- removing a portion of the substrate exposed by the patterned photoresist;
- removing the pattern photoresist; and
- removing a portion of the substrate exposed by the patterned mask to form a cavity and to form at least one first bump over the substrate and in the cavity, and the first bump comprising a plurality of teeth over a stop surface of the first bump.
18. (canceled)
19. The method of claim 17, wherein the substrate comprises at least a movable portion, and the first bump is over the movable portion.
20. The method of claim 17, further comprising following operations:
- forming a metal layer on the substrate;
- patterning the metal layer to form a plurality of protrusions over the substrate;
- forming a patterned mask over the substrate; and
- removing portions of the substrate exposed by the patterned mask to form the first bump comprising the teeth and at least a second bump, wherein the protrusions are over the second bump.
21. The MEMS device according claim 7, further comprising a third structure comprising a third side facing the second structure.
22. The MEMS device according to claim 21, wherein the third structure comprises at least a third bump over the third side.
23. The MEMS device according to claim 22, wherein the third bump comprise a plurality of third teeth over a surface of the third bump.
24. The MEMS device according to claim 23, wherein the third teeth and the third bump comprise different materials.
25. The MEMS device according to claim 23, wherein at least one of the third teeth is electrically coupled to a metal feature in the third structure.
26. The MEMS device according to claim 23, wherein the first teeth and the third teeth comprise different materials.
27. The MEMS device according to claim 12, wherein the second structure comprises a first electrode, and the movable portion of the first structure comprises a second electrode.
28. The MEMS device according to claim 27, further comprising a protection film over the movable portion.
Type: Application
Filed: Jun 29, 2017
Publication Date: Nov 22, 2018
Inventors: SHANG-YING TSAI (TAOYUAN COUNTY), KUEI-SUNG CHANG (KAOHSIUNG CITY), YUEH KANG LEE (HSINCHU CITY)
Application Number: 15/637,154