Methods and structure for adapting MEMS structures to form electrical interconnections for integrated circuits
Methods and structure for adapting MEMS structures to form electrical interconnections for integrated circuits. A first portion and a second portion of the metal conductor, which can be electrically isolated within a CMOS IC device, can be etched to form an unetched portion of the metal conductor. The MEMS device can be patterned, from a MEMS layer formed overlying the metal conductor, via a plasma etching process, during which the unetched portion of the metal conductor is protected from the plasma. The metal conductor can be electrically coupled to the CMOS IC device via a conductive jumper or the like. Furthermore, the integrated CMOS-MEMS device can include a MEMS device coupled to a CMOS IC device via an electrically isolated metal conductor within the CMOS IC device. Also, the metal conductor can be electrically coupled to the substrate of the CMOS IC device via a conductive jumper.
1. A method for manufacturing a CMOS-MEMS integrated device, the method comprising:
providing a CMOS integrated circuit device having a substrate and a metal conductor, the metal conductor being electrically isolated from the substrate;
etching a first portion and a second portion of the metal conductor within the CMOS integrated circuit device to form an unetched portion of the metal conductor;
forming a MEMS layer overlying the CMOS integrated circuit device, the MEMS layer being coupled to the metal conductor;
patterning the MEMS layer with a plasma etching process to form a MEMS device overlying the CMOS integrated circuit device, the MEMS device being formed overlying the unetched portion of the metal conductor, wherein the unetched portion of the metal conductor is protected from the plasma during the plasma etching process, wherein the first portion of the metal conductor is etched to remove a portion that would be directly exposed to plasma during the plasma etching process, wherein the second portion of the metal conductor is etched to remove a portion that would be indirectly exposed to plasma during the plasma etching process; and
electrically coupling the metal conductor to the substrate of the CMOS integrated circuit device.
2. The method of claim 1 wherein the MEMS device is formed with a vertical distance to the metal conductor that is greater than approximately 2 microns.
3. The method of claim 1 wherein the width of the metal conductor ranges from approximately 0.5 microns to 1 micron.
4. The method of claim 1 wherein the unetched portion of the metal conductor has a smaller area than an unetched portion of the MEMS device disposed thereabove.
5. The method of claim 1 wherein electrically coupling the metal conductor to the substrate of the CMOS integrated circuit device comprises forming a conductive jumper coupling the conductor to the substrate.
6. The method of claim 1 wherein the MEMS device is selected from a group consisting of: an accelerometer, a gyroscope, a pressure sensor, a motion detector, a magnetic sensor.
7. The method of claim 1 further comprising forming a conductive shielding material overlying the CMOS integrated circuit device, the conductive shielding material being spatially disposed between the CMOS integrated circuit device and the MEMS layer and electrically insulated from the CMOS integrated circuit device and the MEMS device, the conductive shielding material being configured to protect the MEMS layer from coupling noise.
8. The method of claim 1 further comprising forming a charge protection circuit, the charge protection circuit being operably coupled to the CMOS integrated circuit device, the forming of the charge protection circuit including forming a junction element and a resistive element, the junction element and resistive element being operably coupled to at least an amplifier within the CMOS device and the MEMS device.
9. The method of claim 1 further comprising patterning a wall structure surrounding the MEMS device; and further comprising forming an encapsulation overlying the MEMS device and the wall structure, the wall structure being configured to provide debris protection for the MEMS device during the forming of the encapsulation.
10. The method of claim 1 further comprising forming a matched passive shield circuit, the matched passive shield circuit being operably coupled to the CMOS integrated circuit device, the forming of the matched passive shield circuit including forming a capacitive element and a resistive element coupled in parallel to a DC bias point.