MEMS-microphone
View Patent ↗A MEMS microphone having an improved noise performance due to reduced DC leakage current is provided. For that, a minimum distance between a signal line of the MEMS microphone and other conducting structures is maintained. Further, a DC guard structure fencing at least a section of the signal line is provided.
1. A MEMS-microphone comprising a MEMS-transducer having a signal output, an IC-chip having a signal input, a substrate, a signal line, a conducting structure, and a bump connection between the substrate and the MEMS-transducer or between the substrate and the IC-chip forming a part of the signal line; where
the MEMS-transducer and the IC-chip are arranged on the substrate,
the signal line electrically connects the signal output of the MEMS-transducer with the signal input of the IC-chip,
a DC bias voltage is provided by the IC-chip to the MEMS-transducer via the signal line,
the conducting structure is electrically connected to a DC potential different from the DC bias voltage, and
a minimum lateral distance between the signal line and the conducting structure is kept of at least 200 μm.
2. The MEMS-microphone of claim 1 , where the lateral distance between the signal line and the conducting structure is at least 500 μm.
3. The MEMS-microphone of claim 1 , where the conducting structure comprises an area having a recess in the vicinity of the signal line for maintaining a minimum distance between the conducting structure and the signal line.
4. The MEMS-microphone of claim 1 , where
the MEMS-microphone has an electromagnetic shielding potential, and
the conducting structure is electrically connected to the electromagnetic shielding potential.
5. The MEMS-microphone of claim 1 , where
the MEMS-microphone has a ground potential and
the conducting structure is electrically connected to the ground potential.
6. The MEMS-microphone of claim 1 , where
the substrate comprises two dielectric layers and a metallization layer between the two dielectric layers, and
a section of the signal line is arranged within the metallization layer.
7. The MEMS-microphone of claim 1 , further comprising a DC guard structure fencing a section of the signal line towards adjacent conducting structures having a DC potential different from the DC bias voltage.
8. The MEMS-microphone of claim 1 , where the substrate is an organic laminate comprising a material that includes an FR-4 material, an FR-5 material, polytetrafluoroethylene, or a glass fiber reinforced material.
9. The MEMS-microphone of claim 1 , where the substrate comprises a material that includes a high temperature cofired ceramic, low temperature cofired ceramic, or glass.
10. The MEMS-microphone of claim 1 , wherein a section of the signal line is arranged within the substrate in the form of a metallization layer or on a surface of the substrate.
11. A MEMS-microphone, comprising a MEMS-transducer having a signal output, an IC-chip having a signal input, a substrate, a signal line, a bump connection between the substrate and the MEMS-transducer or between the substrate and the IC-chip forming a part of the signal line, and a DC guard structure; where
the MEMS-transducer and the IC-chip are arranged on the substrate,
the signal line electrically connects the signal output of the MEMS-transducer with the signal input of the IC-chip,
a DC bias voltage is provided by the IC-chip to the MEMS-transducer via the signal line, and
the DC guard structure fences a section of the signal line towards adjacent conducting structures having a DC potential different from the DC bias voltage.
12. The MEMS-microphone of claim 11 , further comprising a signal amplifier, a resistive bias element, and a DC bias source; where
the MEMS-transducer is connected to the DC bias voltage via the resistive bias element, and
the DC guard structure is electrically connected to the DC bias source.
13. The MEMS-microphone of claim 11 , where the DC guard structure comprises a conducting material and a section of the signal line is arranged above or below the DC guard structure.
14. The MEMS-microphone of claim 11 , where
the substrate comprises two dielectric layers, a metallization layer between (a) the two dielectric layers and (b) an upper and a lower metallization layer of the DC guard structure,
a section of the signal line is arranged within the metallization layer, and
the section of the signal line is arranged between the upper metallization and the lower metallization of the DC guard structure.
15. The MEMS-microphone of claim 11 , where the DC guard structure comprises a metallization that is arranged annularly around the signal line.
16. The MEMS-microphone of claim 11 , where the substrate is an organic laminate comprising a material that includes an FR-4 material, an FR-5 material, polytetrafluoroethylene, or a glass fiber reinforced material.
17. The MEMS-microphone of claim 11 , further comprising an electromagnetic shielding structure shielding a section of the signal line.
18. The MEMS-microphone of claim 17 , where the electromagnetic shielding structure shields a section of the DC guard structure.
19. A MEMS-microphone, comprising a MEMS-transducer having a signal output, an IC-chip having a signal input, a substrate, a signal line, a bump connection between the substrate and the MEMS-transducer or between the substrate and the IC-chip forming a part of the signal line, and a conducting structure; where
the MEMS-transducer and the IC-chip are arranged on the substrate,
the signal line electrically connects the signal output of the MEMS-transducer with the signal input of the IC-chip,
a DC bias voltage is provided by the IC-chip to the MEMS-transducer via the signal line, and
the signal line and the conducting structure are electrically isolated.