Micro-electro-mechanical component with gap control structure and manufacturing method of micro-electro-mechanical component

Abstract

The present disclosure describes a microelectromechanical component having a gap control structure and a method for manufacturing the microelectromechanical component. The gap control structure includes a bracket and an adjacent eutectic anchor inside the MEMS element. The bracket provides accurate control of gap height during eutectic bonding of components, while the anchor improves mechanical anchoring of the bracket.

Description

Technical Field

[0001] The present disclosure relates to electronic devices, and more particularly to micro-electromechanical components. The present disclosure also relates to eutectic bonding of micro-electromechanical components having gap control structures. Background Art

[0002] Microelectromechanical systems (MEMS) are a technology of miniature devices that combine mechanical and electrical features. MEMS devices, also known as MEMS elements, can have simple or complex structures with various moving parts. They include devices such as gyroscopes, accelerometers, magnetometers, and pressure sensors. MEMS devices can be manufactured from silicon wafers using micromachining techniques.

[0003] Electronic chips, also called wafers, are prepared by manufacturing various electronic structures on a substrate and cutting the substrate into chip-sized pieces. These chips can be MEMS devices. Several MEMS elements can be built on the same wafer. This allows for significant cost and area reductions. Once the MEMS elements are built, they may need to be sealed in a specific environment, depending on their function.

[0004] Eutectic bonding, also known as eutectic welding, is a well-established semiconductor bonding technology that involves bonding wafers together using a seal formed by two or more metal films that transform into a eutectic alloy at a specific temperature (eutectic temperature) by high pressure. Due to their simple preparation technology and good wettability, eutectic alloys form excellent seals in electronic devices. Eutectic bonding is widely used in MEMS technology for hermetic sealing of MEMS components. During the bonding process, at the eutectic temperature, the eutectic alloy is in the liquid phase. Because the bonding process involves pressing the wafers together under high pressure, in some cases, it can be challenging to accurately control the gap height between the bonded wafers and therefore the MEMS element cavity height due to the softness of the liquid eutectic alloy. Summary of the invention

[0005] The purpose of the present disclosure is to provide a solution to the above-mentioned problem. The disclosed solution allows MEMS vertical gap height control in eutectic bonded micro-electro-mechanical components. The examples provided in the present disclosure describe the way to implement the solution. The improvement is achieved through the features and manufacturing methods of the micro-electro-mechanical components.

[0006] The objects of the present disclosure are achieved by an arrangement which is characterized by what is stated in the independent claim. Preferred embodiments of the present disclosure are disclosed in the dependent claims.

[0007] The present disclosure is based on the concept of a structure comprising a standoff and an adjacent eutectic anchor inside a MEMS element. The standoff provides accurate control of the MEMS gap height during eutectic bonding of the components, while the anchor improves the mechanical anchoring of the standoff. The structure provides new improvements in gap control and robustness of eutectic bonding in micro-electromechanical components. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the following, the present disclosure will be described in more detail by means of preferred embodiments with reference to the accompanying drawings, in which:

[0009] Figure 1 A bottom view of a cover wafer and a top view of a structure wafer are shown, the structure wafer including a gap control area and a sealing area;

[0010] Figure 2a A simplified example of a bottom view of a cover wafer and a top view of a structure wafer in a micro-electromechanical component is shown. A metal layer is attached to the bottom surface of the cover wafer in the cover wafer gap control area;

[0011] Figure 2b Shown include Figure 2a Cross-sectional view of the MEMS components of the cover wafer and the structure wafer shown in In this example, the support has a truncated pyramid shape;

[0012] Figure 2c Another simplified example of a bottom view of a cover wafer and a top view of a structure wafer in a micro-electromechanical component is shown. In this example, the support has a columnar shape;

[0013] Figure 2d Shown include Figure 2c A cross-sectional view of the MEMS components of the cover wafer and the structure wafer shown in FIG.

[0014] Figure 3a to Figure 3c Different possible shapes and locations of eutectic anchors in a micro-electromechanical component are shown;

[0015] Figure 4a to Figure 4b A simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure is shown. A cover wafer includes a conductive via;

[0016] Figure 5a to Figure 5f A simplified illustration of an example method for fabricating a microelectromechanical component having a gap control structure is provided;

[0017] Figure 6a to Figure 6b A simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure before and after bonding is shown. In this example, the eutectic anchor includes a metalloid layer;

[0018] Figure 7a to Figure 7bAnother simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure is shown, wherein the eutectic anchor includes a metalloid layer;

[0019] Figure 8a to Figure 8b Another simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure before and after bonding is shown.The eutectic anchor includes a metalloid layer. DETAILED DESCRIPTION

[0020] The present disclosure describes a micro-electromechanical component including a cover wafer and a structural wafer. The cover wafer has a top surface and a bottom surface. The top surface of the cover wafer defines a horizontal xy plane and a vertical z direction perpendicular to the xy plane. The cover wafer includes a cover wafer sealing area and a cover wafer gap control area, and the cover wafer sealing area surrounds the cover wafer gap control area. The structural wafer has a top surface and a bottom surface, and the top surface of the structural wafer is parallel to the xy plane. The structural wafer includes a structural wafer sealing area and a structural wafer gap control area, and the structural wafer sealing area surrounds the structural wafer gap control area. The cover wafer and the structural wafer are bonded to each other by eutectic sealing, and the eutectic sealing connects the cover wafer sealing area to the structural wafer sealing area, so that the cover wafer gap control area is aligned with the structural wafer gap control area along the z axis. The micro-electromechanical component also includes a metal layer. The metal layer is located at the bottom surface of the cover wafer in the cover wafer gap control area. The structural wafer also includes a bracket in the structural wafer gap control area. The support protrudes outward from the top surface of the structure wafer in the z direction and extends so that it meets the metal layer. The micro-electromechanical component also includes at least one eutectic anchor, which is attached to the top surface of the structure wafer in the structure wafer gap control area adjacent to the support. The eutectic anchor extends from the top surface of the structure wafer to the bottom surface of the cover wafer in the z direction.

[0021] Any direction or plane parallel to the xy plane defined by the cover wafer may be referred to as horizontal. Directions perpendicular to the xy plane may be referred to as vertical directions. Expressions such as "top," "bottom," "above," "below," "up," and "down" refer in this disclosure to differences in vertical z-coordinates. These expressions do not imply anything about how the device should be oriented, taking into account the earth's gravitational field, when the component is in use or when the component is manufactured.

[0022] Figure 1An example of a bottom view of a cover wafer and a top view of a structure wafer is shown. The cover wafer 100 includes a cover wafer gap control area 103 and a cover wafer sealing area 102. In this example, the cover wafer sealing area 102 is adjacent to the edge of the cover wafer. The cover wafer sealing area 102 surrounds the cover wafer gap control area 103. Similarly, the structure wafer 101 includes a structure wafer gap control area 105 and a structure wafer sealing area 104. In this example, the structure wafer sealing area 104 is adjacent to the edge of the structure wafer. The structure wafer sealing area 104 surrounds the structure wafer gap control area 105. The cover wafer 100 and the structure wafer 101 can be bonded to each other so that the eutectic seal connects the cover wafer sealing area 102 to the structure wafer sealing area 104, and the cover wafer gap control area 103 is aligned with the structure wafer gap control area 105 along the z-axis.

[0023] Figure 2a A simplified example of a bottom view of a cover wafer and a top view of a structure wafer in a micro-electromechanical component is shown. In this example, the cover wafer 200 includes a cover wafer sealing area 202 adjacent to the edge of the cover wafer 200. The cover wafer 200 also includes a cover wafer gap control area 203. The cover wafer sealing area 202 surrounds the cover wafer gap control area 203. A metal layer 206 is attached to the bottom surface of the cover wafer 200 in the cover wafer gap control area 203. In this example, the metal layer 206 extends to the outside of the cover wafer gap control area. Alternatively, the metal layer can be located in the cover wafer gap control area 203. These options can be applied to any embodiment in the present disclosure. The structure wafer 201 includes a structure wafer sealing area 204. In this example, the structure wafer sealing area 204 is adjacent to the edge of the structure wafer 201. The structure wafer 201 also includes a structure wafer gap control area 205. The structural wafer sealing area 204 surrounds the structural wafer gap control area 205. The structural wafer 201 also includes a bracket 207 located in the structural wafer gap control area 205. The bracket 207 protrudes outward from the top surface of the structural wafer 201 in the z direction. The micro-electromechanical component may include a plurality of brackets. The bracket shape may be, for example, a truncated pyramid shape or a columnar shape. The columnar shape may be, but is not limited to, a cylinder, a hexagonal prism, or a cuboid. These options may be applied to any embodiment of the present disclosure. In this example, the bracket 207 has a truncated pyramid shape.

[0024] Figure 2b Shown include Figure 2a2 is a cross-sectional view of a micro-electromechanical component of a cover wafer and a structure wafer as shown in FIG. The cover wafer 200 and the structure wafer 201 are bonded to each other by a eutectic seal 209, which connects the cover wafer sealing area to the structure wafer sealing area so that the cover wafer gap control area is aligned with the structure wafer gap control area along the z-axis. A support 207 having a truncated pyramid shape protrudes outward from the top surface of the structure wafer 201 in the z-direction and extends so that it meets the metal layer 206. The micro-electromechanical component also includes a eutectic anchor 208, which is attached to the top surface of the structure wafer 201 in the structure wafer gap control area adjacent to the support. The eutectic anchor 208 extends from the top surface of the structure wafer 201 to the bottom surface of the cover wafer 200 in the z-direction. In any direction parallel to the xy plane, the distance between the eutectic anchor and the support can be less than the distance between the eutectic seal and the support. In any direction parallel to the xy plane, the distance between the eutectic anchor and the support may be in the range of [5 to 100] μm, or [10 to 50] μm, or [20 to 80] μm, or [50-60] μm. The support 207 and the eutectic anchor 208 form a gap control structure.

[0025] The metal layer 206 may be made of various metals, including but not limited to Al, Cu, Ag, Au, Pt, Pd, Mo or metal alloys. The metal layer may be formed by various deposition methods such as sputtering, chemical vapor deposition, molecular beam epitaxy, electron beam physical vapor evaporation or laser metal deposition. The thickness of the metal layer 206 may be in the range of [0.1 to 1.0] μm, or [0.1 to 0.5] μm, or [0.3 to 0.7] μm. The eutectic anchor may be made of a eutectic alloy, which is formed of two or more metals, including but not limited to Au-Sn, Au-In or Cu-Sn. These metals may be formed by various deposition methods such as sputtering, chemical vapor deposition, molecular beam epitaxy, electron beam physical vapor evaporation or laser metal deposition. Alternatively, the eutectic anchor may be made of an alloy including a metalloid. For example, the eutectic anchor may be made of Ge, Al and Ti, or the eutectic anchor may be made of Ge and Al. The eutectic anchor and the eutectic seal may be made of the same eutectic alloy. Alternatively, the eutectic anchor and the eutectic seal may be made of different eutectic alloys. These options may apply to any embodiment in the present disclosure.

[0026] The structure wafer can be a semiconductor device layer that has been attached to a support layer (not shown). The device layer can be a silicon layer. The device layer and the support layer can be, for example, parts of a silicon-on-insulator (SOI) substrate, where the MEMS element can be formed by patterning the top silicon layer (device layer). The cover wafer can be an insulating wafer, such as a glass layer, or a wafer including a semiconductor portion and an insulating portion, or a wafer including a metal portion and an insulating portion. These options can be applied to any embodiment in the present disclosure.

[0027] Figure 2c Another simplified example of a bottom view of a lid wafer and a top view of a structure wafer in a micro-electromechanical component is shown. In this example, the support 217 has a columnar shape. Figure 2c Reference numerals 210, 211, 212, 213, 214, 215 and 216 in the diagram correspond to Figure 2a Reference numerals 200, 201, 202, 203, 204, 205 and 206 in FIG.

[0028] Figure 2d Shown include Figure 2c 2 is a cross-sectional view of a micro-electromechanical component of a cover wafer and a structural wafer as shown in . The cover wafer 210 and the structural wafer 211 are bonded to each other by a eutectic seal 219, which connects the cover wafer sealing area to the structural wafer sealing area so that the cover wafer gap control area is aligned with the structural wafer gap control area along the z-axis. The bracket 217 has a cylindrical shape. The micro-electromechanical component also includes a eutectic anchor 218, which is attached to the top surface of the structural wafer 211 in the structural wafer gap control area adjacent to the bracket. The eutectic anchor 218 extends from the top surface of the structural wafer 211 to the bottom surface of the cover wafer 210 along the z-direction. The bracket 217 and the eutectic anchor 218 form a gap control structure. Figure 2d Reference numeral 216 in corresponds to Figure 2a The reference numeral 206 in FIG.

[0029] The micro-electromechanical component may include one or more eutectic anchors. The plurality of eutectic anchors may be substantially uniformly distributed around the support. Alternatively, a single eutectic anchor may surround the support. The ratio of the surface area of ​​the eutectic anchor in the xy plane to the surface area of ​​the support in the xy plane may be in the range of [1:10 to 10:1] or [1:3 to 3:1].

[0030] Figure 3a to Figure 3c Different possible shapes and positions of eutectic anchors in a micro-electromechanical component are shown. Figure 3a An example of a simplified top view of a structure wafer 301 in a micro-electro-mechanical component is shown. In this example, the micro-electro-mechanical component comprises a single eutectic anchor 308 adjacent to a standoff 307 . Figure 3aReference numerals 304 and 305 in the diagram correspond to Figure 2a Reference numerals 204 and 205 in FIG. Figure 3a Reference numeral 309 in corresponds to Figure 2b The figure mark 209 in FIG.

[0031] Figure 3b Another example of a simplified top view of a structure wafer in a micro-electro-mechanical component is shown. In this example, the micro-electro-mechanical component comprises two eutectic anchors 318 adjacent to a support 317. The eutectic anchors 318 are located on different sides of the support 317 opposite to each other. Figure 3b Reference numerals 311, 314 and 315 in the figure correspond to Figure 2a Reference numerals 201, 204 and 205 in FIG. Figure 3b Reference numeral 319 in corresponds to Figure 2b The figure mark 209 in FIG.

[0032] Figure 3c Another example of a simplified top view of a structure wafer in a micro-electro-mechanical component is shown. In this example, the micro-electro-mechanical component includes one eutectic anchor 328 surrounding a support 327 . Figure 3c Reference numerals 321, 324 and 325 in the figure correspond to Figure 2a Reference numerals 201, 204 and 205 in FIG. Figure 3c Reference numeral 329 in corresponds to Figure 2b The figure mark 209 in FIG.

[0033] The cap wafer may include at least one conductive via, wherein the conductive via extends through the cap wafer along the z-axis so that it meets the metal layer. The conductive via may extend through at least a portion of the thickness of the cap wafer. Alternatively, the conductive via may extend through the entire cap wafer thickness.

[0034] Figure 4a A simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure is shown. The micro-electromechanical component includes a cover wafer 400 and a structure wafer 401, which are bonded together via a eutectic seal 409. In this example, the cover wafer 400 includes a conductive via 4010, which extends through the entire thickness of the cover wafer. The micro-electromechanical component also includes a metal layer 406, which is located at the bottom side of the cover wafer in the cover wafer gap control area. The metal layer 406 extends along the bottom surface of the cover wafer so that it meets the bottom side of the conductive via 4010. The cover wafer can be made of an insulating material such as glass. The conductive via can be a semiconductor via. Alternatively, the conductive via can be a metal via. The metal layer 406 can be connected to an external electrical connection through the conductive via 4010. Figure 4a Reference numerals 407 and 408 in the figure correspond to Figure 2b 207 and 208 in the figure.

[0035] The cover wafer may include a semiconductor portion and an insulating portion, wherein the semiconductor portion is located on top of the insulating portion so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer. The cover wafer may also include at least one conductive via. The conductive via may extend along the z-axis from the bottom side of the semiconductor portion to the bottom side of the insulating portion so that the insulating portion surrounds the side of the conductive via. The metal layer may extend along the bottom surface of the insulating portion so that it meets the bottom side of the conductive via.

[0036] Alternatively, the cover wafer may include a metal portion and an insulating portion, wherein the metal portion is located on top of the insulating portion so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer. The cover wafer may also include at least one conductive via. The conductive via may extend along the z-axis from the bottom side of the metal portion to the bottom side of the insulating portion so that the insulating portion surrounds the side of the conductive via. The metal layer may extend along the bottom surface of the insulating portion so that it meets the bottom side of the conductive via.

[0037] Figure 4b Another example of a cross-sectional view of a micro-electromechanical component with a gap control structure is shown. The micro-electromechanical component includes a cover wafer 410 and a structure wafer 411, which are bonded together via a eutectic seal 419. In this example, the cover wafer includes a semiconductor portion and an insulating portion. The semiconductor portion 4111 is located on top of the insulating portion 4112, so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer. The cover wafer 410 also includes a conductive via 4110, which extends from the bottom side of the semiconductor portion 4111 to the bottom side of the insulating portion 4112 along the z-axis, so that the insulating portion surrounds the side of the conductive via 4110. The micro-electromechanical component also includes a metal layer 416, which is located at the bottom side of the cover wafer in the cover wafer gap control area. The metal layer 416 extends along the bottom surface of the insulating portion so that it meets the bottom side of the conductive via 4110. The conductive via can be a semiconductor via. Alternatively, the conductive vias may be metal vias. The metal layer 416 may be connected to an external electrical connection through the conductive vias 4110. The structural wafer 411 includes a support 417 located in the gap control region of the structural wafer. The support 417 protrudes outward from the top surface of the structural wafer 411 in the z direction so that it meets the metal layer 416. The support 417 and the metal layer 416 may be used as good ohmic press-on contacts inside the element. The support 417 and the adjacent eutectic anchor 418 serve as accurate gap height control structures because the eutectic anchor 418 helps ensure stable contact between the support 417 and the metal layer 416. In addition, the eutectic anchor increases the mechanical strength of the structure, making it robust in life testing.

[0038] Figure 5a to Figure 5f A simplified illustration of an example method for manufacturing a micro-electromechanical component with a gap control structure is provided. The micro-electromechanical component includes a cover wafer and a structural wafer. The cover wafer has a top surface and a bottom surface. The top surface of the cover wafer defines a horizontal xy plane and a vertical z direction perpendicular to the xy plane. The cover wafer includes a cover wafer sealing area and a cover wafer gap control area, and the cover wafer sealing area surrounds the cover wafer gap control area. The structural wafer has a top surface and a bottom surface. The top surface of the structural wafer is parallel to the xy plane. The structural wafer includes a structural wafer sealing area and a structural wafer gap control area, and the structural wafer sealing area surrounds the structural wafer gap control area.

[0039] The method includes: (1) forming a first metal layer on the bottom surface of the lid wafer in the lid wafer gap control region, (2) forming a second metal layer adjacent to the first metal layer on the bottom surface of the lid wafer in the lid wafer gap control region, (3) forming a standoff in the structure wafer gap control region so that the standoff protrudes and extends outward from the top surface of the structure wafer in the z direction; (4) forming a third metal layer adjacent to the standoff on the top surface of the structure wafer in the structure wafer gap control region, (5) placing the lid wafer on top of the structure wafer so that the first metal layer is aligned with the standoff along the z axis and the second metal layer is aligned with the third metal layer along the z axis, (6) bonding the lid wafer sealing region to the structure wafer sealing region so that the top surface of the standoff is connected to the first metal layer and the second metal layer and the third metal layer form a eutectic anchor. The above-mentioned component can include any structural features included in the following presentation of the manufacturing method.

[0040] The structural wafer may be a semiconductor device layer that has been attached to a support layer. The device layer may be a silicon layer. The device layer and the support layer may, for example, be part of a silicon-on-insulator (SOI) substrate, where the MEMS element may be formed by patterning the top silicon layer (device layer).

[0041] The method for manufacturing a micro-electromechanical component with a gap control structure may include the following steps: before forming the third metal layer, forming a dielectric / insulating layer on the top surface of the structural wafer. The dielectric / insulating layer has the advantage of preventing possible chemical reactions between the eutectic anchor and the structural wafer. The dielectric / insulating layer may be an oxide or a nitride, such as SiO2, ZrO2, HfO2, Ta2O3, or SiNx. This option may be applied to any embodiment in the present disclosure.

[0042] The cover wafer may be an insulating wafer such as a glass layer, or a wafer including a semiconductor portion and an insulating portion, or a wafer including a metal portion and an insulating portion. The cover wafer may, for example, include a semiconductor portion and an insulating portion, wherein the semiconductor portion is located on top of the insulating portion so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer. The cover wafer may also include at least one conductive via. The conductive via may extend along the z-axis from the bottom side of the semiconductor portion to the bottom side of the insulating portion so that the insulating portion surrounds the side of the conductive via. The first metal layer may extend along the bottom surface of the insulating portion so that it meets the bottom side of the conductive via.

[0043] Figure 5a One of the first steps of an example method for manufacturing a micro-electromechanical component with a gap control structure is shown. In this example, a cover wafer 500 includes a semiconductor portion 5011 and an insulating portion 5012. The semiconductor portion 5011 is located on top of the insulating portion 5012, so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer 500. The cover wafer 500 also includes a conductive via 5010, which extends from the bottom side of the semiconductor portion 5011 to the bottom side of the insulating portion 5012 along the z-axis, so that the insulating portion surrounds the side of the conductive via 5010. This step includes: forming a first metal layer 506 on the bottom surface of the cover wafer 500 in the cover wafer gap control area, so that the first metal layer 506 meets the bottom of the conductive via 5010. The first metal layer can be made of various metals, including but not limited to Al, Cu, Ag, Au, Pt, Pd, Mo or metal alloys. The first metal layer can be formed by various deposition methods such as sputtering, chemical vapor deposition, molecular beam epitaxy, electron beam physical vapor evaporation, or laser metal deposition. The thickness of the first metal layer 506 can be in the range of [0.1 to 1.0] μm, or [0.1 to 0.5] μm, or [0.3 to 0.7] μm. The conductive via can be a semiconductor via. Alternatively, the conductive via can be a metal via.

[0044] Figure 5b Another step in the method for manufacturing a micro-electromechanical component with a gap control structure is shown. In this step, a second metal layer 5113 is formed on the bottom surface of the cover wafer in the cover wafer gap control area, adjacent to the first metal layer 506. A first additional metal layer 5114 can be formed in the cover wafer sealing area at the same time. The second metal layer 5113 and the first additional metal layer 5114 can be made of the same metal. Alternatively, the second metal layer 5113 and the first additional metal layer 5114 can be made of different metals.

[0045] Figure 5cAnother step in the method for manufacturing a micro-electromechanical component with a gap control structure is shown. In this step, a support 527 is formed in the structure wafer gap control region so that the support protrudes and extends outward from the top surface of the structure wafer 521 in the z direction. The support 527 can be formed by a semiconductor microfabrication technology such as a local oxidation (LOCOS) process, a wet etching process, or a dry etching process.

[0046] Figure 5d Another step in the method for manufacturing a micro-electromechanical component with a gap control structure is shown. In this step, a third metal layer 5315 is formed on the top surface of the structure wafer 521 in the structure wafer gap control area, adjacent to the support 527. A second additional metal layer 5316 can be formed in the structure wafer sealing area at the same time. The third metal layer 5315 and the second additional metal layer 5316 can be made of the same metal. Alternatively, the third metal layer 5315 and the second additional metal layer 5316 can be made of different metals.

[0047] The second metal layer 5113 and the third metal layer 5315 may be made of any metal that forms a eutectic alloy at the corresponding eutectic temperature. The first additional metal layer 5114 and the second additional metal layer 5316 may be made of any metal that forms a eutectic alloy at the corresponding eutectic temperature. Such metals may include, but are not limited to, Au-Sn, Au-In, or Cu-Sn. These options may apply to any embodiment in the present disclosure.

[0048] Figure 5e Steps of a method for manufacturing a microelectromechanical component are shown, wherein a cap wafer 500 is placed on top of a structure wafer 521 such that the first metal layer 506 is aligned with the support 527 along the z-axis and the second metal layer 5113 is aligned with the third metal layer 5315 along the z-axis.

[0049] Figure 5f The final step of an example method for manufacturing a micro-electromechanical component with a gap control structure is shown. In this step, the cover wafer 500 and the structure wafer 521 are pressed together at a specific eutectic temperature. Therefore, the cover wafer sealing area and the structure wafer sealing area are bonded together by the eutectic seal 549 formed by the chemical reaction between the first additional metal layer 5114 and the second additional metal layer 5316. At the same time, the bracket 527 contacts the first metal layer 506, and the eutectic anchor 548 is formed by the chemical reaction between the second metal layer 5113 and the third metal layer 5315. The eutectic temperature can be in the range of [300 to 500]°C, [400-450]°C, or [420-450]°C.

[0050] The support 527 and the first metal layer 506 can be used as good ohmic pressure contact inside the MEMS element after eutectic bonding. The support 527 and the adjacent eutectic anchor 548 form an accurate gap height control structure because the eutectic anchor 548 helps to ensure stable contact between the support 527 and the first metal layer 506.

[0051] The method for manufacturing a micro-electromechanical component with a gap control structure may also include the following steps: before placing a cover wafer on top of the structure wafer, forming a semi-metallic layer on top of the third metal layer, and then bonding the cover wafer to the structure wafer so that the second metal layer, the third metal layer and the semi-metallic layer form a eutectic anchor.

[0052] Figure 6a An example of a micro-electromechanical component before the cap wafer and the structure wafer are bonded together is shown. In this example, a metalloid layer 6017 is formed on top of the third metal layer 6015 before the eutectic bonding step. At the same time, an additional metalloid layer 6018 may be formed on top of the second additional metal layer 6016 before the eutectic bonding step. In such a structure, the second metal layer 6013 may be an Al layer, the third metal layer 6015 may be a Ti layer, and the metalloid layer 6017 may be a Ge layer. Figure 6a Reference numerals 600, 601, 606, 607, 6010, 6011, 6012 and 6014 in the drawings correspond to Figure 5e Reference numerals 500, 521, 506, 527, 5010, 5011, 5012 and 5114 in the drawings.

[0053] Figure 6b 6 shows the structure of the cap wafer 600 and the structure wafer 601 after eutectic bonding at the eutectic temperature. Figure 6a The cover wafer sealing area and the structure wafer sealing area are bonded together by a eutectic seal 619 formed by a chemical reaction between the first additional metal layer 6014, the second additional metal layer 6016 and the additional metalloid layer 6018. At the same time, the standoff 607 meets the first metal layer 606, and a eutectic anchor 618 is formed by a chemical reaction between the second metal layer 6013, the third metal layer 6015 and the metalloid layer 6017. Figure 6b Reference numerals 6010, 6011 and 6012 in the figure correspond to Figure 5a 5010, 5011 and 5012 in the figure.

[0054] Alternatively, the method for manufacturing a micro-electromechanical component may further include the following steps: before placing a lid wafer on top of the structure wafer, forming a metalloid layer at the bottom of the second metal layer, and then bonding the lid wafer and the structure wafer together so that the second metal layer, the third metal layer and the metalloid layer form a eutectic anchor.

[0055] Figure 7a Another example of a micro-electromechanical component before the cap wafer and the structure wafer are bonded together is shown. In this example, a metalloid layer 7017 is formed at the bottom of the second metal layer 7013 before the eutectic bonding step. At the same time, an additional metalloid layer 7018 can be formed at the bottom of the first additional metal layer 7014 before the eutectic bonding step. Figure 7a Reference numerals 700, 701, 706, 707, 7010, 7011, 7012, 7015 and 7016 in the drawings correspond to Figure 5e 500, 521, 506, 527, 5010, 5011, 5012, 5315 and 5316 in the figure.

[0056] Figure 7b 7 shows the structure of the cover wafer 700 after eutectic bonding the structure wafer 701 together at the eutectic temperature. Figure 7a The cover wafer sealing area and the structure wafer sealing area are bonded together by a eutectic seal 719 formed by a chemical reaction between the first additional metal layer 7014, the second additional metal layer 7016, and the additional metalloid layer 7018. At the same time, the support 707 meets the first metal layer 706, and the eutectic anchor 718 is formed by a chemical reaction between the second metal layer 7013, the third metal layer 7015, and the metalloid layer 7017. The second metal layer can be a Ti layer, the third metal layer can be an Al layer, and the metalloid layer can be a Ge layer. Figure 7b Reference numerals 7010, 7011 and 7012 in the figure correspond to Figure 5a 5010, 5011 and 5012 in the figure.

[0057] Alternatively, the eutectic anchor may be made of a eutectic alloy including only one metal layer and one metalloid layer, such as an Al-Ge eutectic alloy. In such an embodiment, the metalloid layer may be formed on the top surface of the structural wafer or on the bottom surface of the cap wafer. Similarly, the eutectic seal may be made of a eutectic alloy including only one metal layer and one metalloid layer.

[0058] Figure 8aA simplified example of a cross-sectional view of a micro-electromechanical component including a gap control structure before and after bonding is shown. In this example, a metalloid layer 8017 is formed on the top surface of the structure wafer 801 in the structure wafer gap control region adjacent to the support 807. An additional metalloid layer 8018 may be formed on the top surface of the structure wafer in the structure wafer sealing region at the same time. Figure 8a Reference numerals 800, 806, 8010, 8011, 8012, 8013 and 8014 in the figure correspond to Figure 5b Reference numerals 500, 506, 5010, 5011, 5012, 5113 and 5114 in the drawings.

[0059] Figure 8b 800 and the structure wafer 801 are eutectically bonded together at the eutectic temperature. Figure 8a In this example, the cover wafer sealing area and the structure wafer sealing area are bonded together by a eutectic seal 819 formed by a chemical reaction between the first additional metal layer 8014 and the additional metalloid layer 8018. At the same time, the support 807 is in contact with the first metal layer 806, and a eutectic anchor 818 is formed by a chemical reaction between the second metal layer 8013 and the metalloid layer 8017. Figure 8b Reference numerals 8010, 8011 and 8012 in the figure correspond to Figure 5a 5010, 5011 and 5012 in the figure.

Claims

1. A micro-electromechanical component comprising a cover wafer and a structure wafer, in, The lid wafer has a top surface and a bottom surface, the top surface of the lid wafer defining a horizontal xy plane and a vertical z direction perpendicular to the xy plane, and wherein the lid wafer includes a lid wafer sealing area and a lid wafer gap control area, and the lid wafer sealing area surrounds the lid wafer gap control area, and wherein the structural wafer has a top surface and a bottom surface, the top surface of the structural wafer is parallel to the xy plane, and wherein the structural wafer comprises a structural wafer sealing region and a structural wafer gap control region, and the structural wafer sealing region surrounds the structural wafer gap control region, and wherein the lid wafer and the structure wafer are bonded to each other by eutectic sealing connecting the lid wafer sealing region to the structure wafer sealing region such that the lid wafer gap control region is aligned with the structure wafer gap control region along the z-axis, It is characterized in that The micro-electromechanical component further includes a metal layer, wherein the metal layer is located at the bottom surface of the cover wafer in the cover wafer gap control region, and the structure wafer further includes a bracket in the structure wafer gap control region; wherein the bracket protrudes outward from the top surface of the structure wafer along the z direction and extends so that the bracket meets the metal layer, And wherein the micro-electromechanical component further comprises at least one eutectic anchor, wherein the at least one eutectic anchor is attached to a top surface of the structure wafer in the structure wafer gap control region adjacent to the bracket, wherein the eutectic anchor extends from the top surface of the structure wafer to the bottom surface of the cover wafer along the z-direction.

2. The micro-electromechanical component according to claim 1, wherein: The eutectic anchor is made of an alloy including a metalloid.

3. The micro-electromechanical component according to claim 2, wherein: The eutectic anchor is made of Ge, Al and Ti.

4. The micro-electromechanical component according to claim 2, wherein: The eutectic anchor is made of Ge and Al.

5. The micro-electromechanical component according to any one of claims 1 to 4, wherein: The lid wafer includes at least one conductive via, wherein the conductive via extends through the lid wafer along the z-axis such that the conductive via meets the metal layer.

6. The micro-electromechanical component according to claim 5, wherein: The conductive via is a semiconductor via.

7. The micro-electromechanical component according to claim 5, wherein: The conductive via is a metal via.

8. A method for manufacturing a micro-electromechanical component having a gap control structure, wherein: The micro-electromechanical component comprises a cover wafer and a structure wafer, and wherein the cover wafer has a top surface and a bottom surface, the top surface of the cover wafer defining a horizontal xy plane and a vertical z direction perpendicular to the xy plane, and wherein the cover wafer includes a cover wafer sealing area and a cover wafer gap control area, and the cover wafer sealing area surrounds the cover wafer gap control area, and wherein the structural wafer has a top surface and a bottom surface, the top surface of the structural wafer is parallel to the xy plane, and wherein the structural wafer comprises a structural wafer sealing region and a structural wafer gap control region, and the structural wafer sealing region surrounds the structural wafer gap control region, Characterized in that the method comprises: - forming a first metal layer on the bottom surface of the lid wafer in the lid wafer gap control area, - forming a second metal layer adjacent to the first metal layer on the bottom surface of the lid wafer in the lid wafer gap control area, - forming a support in the structure wafer gap control region so that the support protrudes and extends outwardly from the top surface of the structure wafer in the z direction, - forming a third metal layer on the top surface of the structure wafer in the structure wafer gap control region adjacent to the support, - placing the cap wafer on top of the structure wafer such that the first metal layer is aligned with the support along the z-axis and the second metal layer is aligned with the third metal layer along the z-axis, - bonding the lid wafer sealing area and the structure wafer sealing area together such that the top surface of the standoff is connected to the first metal layer and the second metal layer and the third metal layer form a eutectic anchor.

9. The method for manufacturing a micro-electromechanical component according to claim 8, wherein: The method further includes the steps of forming a metalloid layer on top of the third metal layer before placing the lid wafer on top of the structure wafer, and then bonding the lid wafer and the structure wafer together such that the second metal layer, the metalloid layer and the third metal layer form a eutectic anchor.

10. The method for manufacturing a micro-electromechanical component according to claim 9, wherein: The second metal layer is an Al layer, the third metal layer is a Ti layer, and the metalloid layer is a Ge layer.

11. The method for manufacturing a micro-electromechanical component according to claim 8, wherein: The method further includes the steps of forming a metalloid layer at the bottom of the second metal layer before placing the lid wafer on top of the structure wafer, and then bonding the lid wafer and the structure wafer together so that the second metal layer, the metalloid layer and the third metal layer form a eutectic anchor.

12. The method for manufacturing a micro-electromechanical component according to claim 11, wherein: The second metal layer is a Ti layer, the third metal layer is an Al layer, and the metalloid layer is a Ge layer.

13. The method for manufacturing a micro-electromechanical component according to any one of claims 8 to 12, wherein: The cover wafer includes a semiconductor portion and an insulating portion, wherein the semiconductor portion is located on top of the insulating portion so that the bottom surface of the insulating portion forms the bottom surface of the cover wafer; and wherein the cover wafer also includes at least one conductive via, wherein the conductive via extends along the z-axis from the bottom side of the semiconductor portion to the bottom side of the insulating portion so that the insulating portion surrounds the side of the conductive via; and wherein the first metal layer extends along the bottom surface of the insulating portion so that the first metal layer meets the bottom side of the conductive via.

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