TWI514444B - Suspended beam for use in mems device - Google Patents

Description

Suspension beam structure applied in MEMS

The case is a suspension beam structure, especially a suspension beam structure applied in a microelectromechanical system.

Micro Electro-Mechanical Systems (MEMS) mainly uses semiconductor processes to fabricate mechanical structures on germanium wafers, and develops semiconductor sensors that combine mechanical and electronic components. Referring to Figure 1, a top view of a suspension beam structure common in MEMS, in which one end 101 of a suspended beam 10 is fixed to the raft substrate 1 and the other end 100 is suspended. Such a suspension beam structure can be widely applied to a plurality of sensor components. For example, a variable capacitance can be completed by using a distance change between two adjacent suspension beams, thereby completing a sensor component such as an accelerometer. However, the conventional suspension beam structure is not conducive to integration into the control circuit chip, and how to improve such a defect is the main purpose of the development of the case.

An object of the present invention is to provide a suspension beam structure comprising: a substrate; a suspension beam body having one end fixed to the substrate and the other end suspended; and a first metal wire structure embedded in the suspension beam body The width of the first metal wire structure is smaller than the width of the main body of the suspension beam.

In an embodiment of the invention, the substrate is a germanium substrate.

In an embodiment of the invention, the suspension beam main system is composed of a dielectric layer or a plurality of dielectric layers.

In an embodiment of the invention, the material of the dielectric layer is yttrium oxide.

In an embodiment of the invention, the first metal wire structure is embedded in a portion of the top surface of the suspension beam body and exposed.

In an embodiment of the invention, the first metal wire structure is embedded in a peripheral edge of the top surface of the suspension beam body and exposed.

In an embodiment of the invention, the first metal wire structure is embedded in the interior of the suspension beam body and is not exposed.

In an embodiment of the invention, the second metal wire structure is further embedded in the suspension beam body and connected to the first metal wire structure through at least one through hole metal.

A further object of the present invention is to provide a circuit wafer comprising: a substrate; an integrated circuit component structure formed over the substrate having a multi-layer structure; a MEMS structural region formed over the substrate, wherein At least one suspension beam structure comprising: a suspension beam body having one end fixed to the substrate and the other end suspended; and a first metal wire structure embedded in the suspension beam body The width of the first metal wire structure is less than the width of the suspension beam body.

Referring to Figure 2A, which is a top view of an embodiment of a suspension beam structure, it will be apparent from the drawings that one end 201 of the suspension beam 20 is secured to the crucible substrate 2 and the other end 200 is suspended. The top surface of the suspension beam 20 and the ruthenium substrate 2 is covered with a metal layer 202 for completing the electrode plate of the capacitor. The cross-sectional view along the line AA is as shown in FIG. 2B or FIG. 2C, wherein FIG. 2B is a two-layer structure, the suspension beam 20 is composed of the dielectric layer 203 and the metal layer 202, and FIG. 2C is a four-layer structure. The suspension beam 20 is composed of dielectric layers 203, 205 and metal layers 202, 204. The bottom substrate of the suspension beam 20 is etched and hollowed to allow the suspension beam 20 to float. This embodiment is composed only of a dielectric layer and a metal layer, and a simple structure will facilitate integration into a general integrated circuit chip. However, due to the difference in material properties between the dielectric layer and the metal layer, the metal layer is easily bent after the subsequent high-temperature process, and the suspension beam 20 will undergo an unexpected deformation, resulting in the subsequent completion of the sensor element.

Accordingly, the inventors propose another embodiment to improve this problem. Referring to FIG. 3A, it is a top view of the second embodiment of the suspension beam structure developed by the inventors, as can be clearly seen from the figure. One end 301 of the suspension beam 30 is fixed to the 矽 substrate 3, and the other end 300 is suspended by the enamel substrate 3 at the bottom of the suspension beam 30 to hang the suspension beam 30. In the present embodiment, the top surface of the suspension beam 30 will not be completely covered by metal, but surrounded by a metal wire structure 3020 for completing one of the capacitor plates. A cross-sectional view of the suspension beam 30 along line BB can be as shown in FIG. 3B, wherein the main body of the suspension beam 30 is completed by a dielectric layer 303, and the metal wire structure 3020 can be completed by a metal embedded in the dielectric layer 303. Compared with the embodiment shown in FIG. 2A and FIG. 2B, the metal wire structure 3020 of the present embodiment only surrounds the periphery of the top surface of the suspension beam 30, thereby causing the metal wire structure 3020 to cause the suspension beam 30 to be generated due to the high temperature process. The effect of deformation has fallen dramatically.

In addition, the cross-sectional view of the suspension beam 30 along the line segment BB can also be as shown in FIG. 3C or FIG. 3D. The suspension beam 30 can be composed of a plurality of dielectric layers 303, 305 and a plurality of metal wire structures 3020, 3040, FIG. 3C and 3D differs in that the metal wire structures 3020, 3040 in FIG. 3D have a through-hole metal 308 to complete the connection.

Referring to FIG. 4A, which is a top view of another embodiment of the suspension beam structure developed by the inventors, it can be clearly seen that one end 401 of the suspension beam 40 is fixed to the crucible substrate 4 and the other end 400. Then dangling. In the present embodiment, the top surface of the suspension beam 40 is not completely covered by metal, but is covered by a metal wire structure 4020 for completing one of the capacitor plates. A cross-sectional view of the suspension beam 40 along the line CC can be as shown in FIG. 4B, wherein the main body of the suspension beam 40 is completed by a dielectric layer 403, and the metal wire structure 4020 can be completed by a metal embedded in the dielectric layer 403. Compared with the embodiment shown in FIG. 2A and FIG. 2B, the metal wire structure 4020 of the present embodiment is only embedded on a portion of the top surface and the periphery of the dielectric layer 403 and has a width smaller than the width of the dielectric layer 403, thereby making the metal The effect of the wire structure 4020 causing deformation of the suspension beam 40 due to the high temperature process is greatly reduced.

In addition, the cross-sectional view of the suspension beam 40 along the line CC can also be as shown in FIG. 4C or FIG. 4D. The suspension beam 40 can be composed of a plurality of dielectric layers 403, 405 and a plurality of metal wire structures 4020, 4040, FIG. 4C and 4D differs in that the metal wire structures 4020, 4040 in FIG. 4D have a through-hole metal 408 to complete the connection.

Referring again to FIG. 5A, which is a top view of another embodiment of the suspension beam structure developed by the inventors, it can be clearly seen that one end 501 of the suspension beam 50 is fixed to the 矽 substrate 5, and the other end is 500 is suspended. In the present embodiment, the top surface of the suspension beam 50 is not covered by the metal wire at all, and the metal wire structure 5020 required to complete one of the capacitor plates is embedded in the dielectric layer 503 and is not exposed. A cross-sectional view of the suspension beam 50 along the line segment DD can be as shown in FIG. 5B, wherein the main body of the suspension beam 50 is completed by the dielectric layer 503, and the metal wire structure 5020 can be made of metal embedded in the dielectric layer 503 and not exposed. carry out. Compared with the embodiment shown in FIG. 2A and FIG. 2B, the metal wire structure 5020 of the present embodiment is only embedded in the interior of the dielectric layer 503 and has a width smaller than the width of the dielectric layer 503, thereby causing the metal wire structure 5020 to be heated due to high temperature. The effect of the process causing the deformation of the suspension beam 50 is greatly reduced.

In addition, the cross-sectional view of the suspension beam 50 along the line segment DD can also be as shown in FIG. 5C or FIG. 5D. The suspension beam 50 can be composed of a plurality of dielectric layers 503, 505 and a plurality of metal wire structures 5020, 5040, FIG. 5C and 5D differs in that the metal wire structures 5020, 5040 in FIG. 5D have a through-hole metal 508 to complete the connection.

Referring to FIG. 6 , which is a structural cross-sectional view of the suspension beam structure integrated into the integrated circuit chip, it can be seen that the integrated circuit component structure 60 is completed on the germanium substrate 6 , and the integrated circuit is completed. The component structure 60 has a multilayer structure 600 in which a plurality of dielectric layers and a wire layer are alternately stacked, and while the multilayer structure 600 is completed from the bottom up, the microelectromechanical system (MEMS) structure region 61 can also be formed as described above. For example, various metal damascene structures are then etched using the opening pattern defined by the hard mask 62 to etch the damascene structure in the microelectromechanical system (MEMS) construction region 61 and to pry the bottom substrate 6 out of the space 69, Further, a plurality of parallel suspension beam structures 63 are defined. The hard mask 62 can be directly used with the uppermost metal wire layer of the multilayer structure 600, in addition to the metal mask having a better barrier capability. The hard mask 62 is usually defined after the suspension beam structure 63 is completed. It is almost exhausted, but there may be residuals, but the thickness is usually very thin and does not affect the structure, so it can be left untreated, and of course it can be stripped. The dielectric layer can be completed by using yttrium oxide. The metal layer or the metal wire structure can be a common copper wire or a metal material such as aluminum or tungsten, or an alloy of a metal material.

In summary, after the technology of the present invention is improved, the problem of the conventional means can be effectively improved. While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

1. . .矽 substrate

10. . . Suspension beam

100. . . One end of the suspension beam

101. . . The other end of the suspension beam

2. . .矽 substrate

20. . . Suspension beam

200. . . One end of the suspension beam

201. . . The other end of the suspension beam

202. . . Metal layer

203. . . Dielectric layer

204. . . Metal layer

205. . . Dielectric layer

3. . .矽 substrate

30. . . Suspension beam

300. . . One end of the suspension beam

301. . . The other end of the suspension beam

3020. . . Metal wire structure

303. . . Dielectric layer

3040. . . Metal wire structure

305. . . Dielectric layer

308. . . Through hole metal

4. . .矽 substrate

40. . . Suspension beam

400. . . One end of the suspension beam

401. . . The other end of the suspension beam

4020. . . Metal wire structure

403. . . Dielectric layer

4040. . . Metal wire structure

405. . . Dielectric layer

408. . . Through hole metal

5. . .矽 substrate

50. . . Suspension beam

500. . . One end of the suspension beam

501. . . The other end of the suspension beam

5020. . . Metal wire structure

503. . . Dielectric layer

5040. . . Metal wire structure

505. . . Dielectric layer

508. . . Through hole metal

6. . .矽 substrate

60. . . Integrated circuit component construction

600. . . Multilayer structure

61. . . MEMS construction area

62. . . Hard mask

63. . . Suspension beam structure

69. . . space

Figure 1 is a top view of a suspension beam structure commonly found in MEMS.

2A is a top view of an embodiment of a suspension beam structure.

2B is a cross-sectional view of one of the suspension beam structures of FIG. 2A along line AA.

2C is another exemplary cross-sectional view of the suspension beam structure of FIG. 2A along line AA.

3A is a top view of another embodiment of the suspension beam structure of the present invention.

3B is a cross-sectional view of one of the suspension beam structures of FIG. 3A along line BB.

3C is another exemplary cross-sectional view of the suspension beam structure of FIG. 3A along line BB.

3D is another exemplary cross-sectional view of the suspension beam structure of FIG. 3A along line BB.

4A is a top view of still another embodiment of the suspension beam structure of the present invention.

4B is a cross-sectional view of one of the suspension beam structures of FIG. 4A along line CC.

4C is another exemplary cross-sectional view of the suspension beam structure of FIG. 4A along line CC.

4D is another exemplary cross-sectional view of the suspension beam structure of FIG. 4A along line CC.

FIG. 5A is a top view of still another embodiment of the suspension beam structure of the present invention.

Figure 5B is a cross-sectional view of one of the suspension beam structures of Figure 5A along line DD.

Figure 5C is another cross-sectional view of the suspension beam structure of Figure 5A taken along line DD.

Figure 5D is a further cross-sectional view of the suspension beam structure of Figure 5A along line DD.

Fig. 6 is a schematic cross-sectional view showing the structure in which the suspension beam structure of the present invention is integrated into an integrated circuit chip.

3. . .矽 substrate

30. . . Suspension beam

300. . . One end of the suspension beam

301. . . The other end of the suspension beam

3020. . . Metal wire structure

303. . . Dielectric layer

Claims (16)

A suspension beam structure comprising: a substrate; a suspension beam body having one end fixed to the substrate and the other end suspended; and a first metal wire structure embedded in the suspension beam body and surrounding portion The main body of the suspension beam has a width smaller than a width of the main body of the suspension beam. The suspension beam structure of claim 1, wherein the substrate is a substrate. The suspension beam structure of claim 1, wherein the suspension beam main system is composed of a dielectric layer or a plurality of dielectric layers. The suspension beam structure of claim 3, wherein the material of the dielectric layer is ruthenium oxide. The suspension beam structure of claim 1, wherein the first metal wire structure is embedded in a portion of a top surface of the main body of the suspension beam and exposed. The suspension beam structure of claim 1, wherein the first metal wire structure is embedded in a periphery of a top surface of the suspension beam body and exposed. The suspension beam structure of claim 1, wherein the first metal wire structure is embedded in the interior of the suspension beam body and is not exposed. The suspension beam structure of claim 1, wherein the second suspension comprises a second gold The wire structure is embedded in the main body of the suspension beam and is connected to the first metal wire structure through at least one through hole metal. A circuit chip comprising: a substrate; an integrated circuit component structure formed on the substrate and having a multi-layer structure; a MEMS structural region formed on the substrate, wherein at least one suspension beam structure is The suspension beam structure comprises: a suspension beam body, one end of which is fixed to the substrate and the other end is suspended; and a first metal wire structure embedded in the suspension beam body and surrounding the suspension beam body The width of the first metal wire structure is less than the width of the main body of the suspension beam. The circuit chip of claim 9, wherein the main structure of the suspension beam is composed of a dielectric layer or a plurality of dielectric layers. The circuit chip of claim 9, wherein the first metal wire structure is embedded in a portion of a top surface of the main body of the suspension beam and exposed. The circuit chip of claim 9, wherein the first metal wire structure is embedded in a periphery of a top surface of the suspension beam body and exposed. The circuit chip of claim 9, wherein the first metal wire structure is embedded in the interior of the suspension beam body and is not exposed. The circuit chip according to claim 9 of the patent application, which further comprises a second gold The wire structure is embedded in the main body of the suspension beam and is connected to the first metal wire structure through at least one through hole metal. The circuit chip of claim 9, wherein the suspension beam structure forms part of a capacitor. The circuit chip of claim 9, wherein the material of the first metal wire structure is copper, aluminum or tungsten.