Microelectronic assembly having a perimeter around a MEMS device

1. A microelectronic assembly, comprising:

a MEMS substrate;

a MEMS device on the MEMS substrate, the MEMS device having a MEMS component which is movable relative to the MEMS substrate;

a cover piece having a side over a side of the MEMS substrate on which the MEMS device is located; and

a plurality of perimeter components, each having opposing portions sealing with the MEMS substrate and the cover piece respectively, the perimeter components forming a continuous perimeter around the MEMS device to seal the MEMS device.

2. The microelectronic assembly of claim 1 , further comprising:

a plurality of interconnection elements between the MEMS substrate and the cover piece, the cover piece being a carrier substrate and the interconnection elements connecting the carrier substrate electrically to the MEMS substrate.

3. The microelectronic assembly of claim 2 , wherein the interconnection elements are within the perimeter.

4. The microelectronic assembly of claim 3 , wherein each interconnection element includes a respective solder ball and a respective land to which the respective solder ball is soldered, and each perimeter piece includes a respective bar and a respective pad to which the respective bar is soldered.

5. The microelectronic assembly of claim 1 , further comprising:

a thermal interface component placed over the MEMS substrate, heated so that edge portions thereof reflow and drop onto the cover piece over the MEMS device, and allow it to cool.

6. The microelectronic assembly of claim 5 , further comprising:

a heat sink on the thermal interface component.

7. The microelectronic assembly of claim 5 , further comprising:

an electronic component on the thermal interface material; and

wirebonding wires connecting the electronic component with the cover piece over the MEMS device.

8. The microelectronic assembly of claim 5 , further comprising:

a plurality of interconnection elements between the MEMS substrate and the cover piece, the cover piece being the carrier substrate and the interconnection elements connecting the carrier substrate electrically to the MEMS substrate.

9. The microelectronic assembly of claim 8 , wherein the interconnection elements are within the perimeter.

10. The microelectronic assembly of claim 1 , further comprising:

a plurality of interconnection elements between the MEMS substrate and the cover piece, the cover piece being a carrier substrate and the interconnection elements connecting the carrier substrate electrically to the MEMS substrate, the interconnection elements being located outside the perimeter.

11. The microelectronic assembly of claim 10 , wherein each interconnection element includes a respective solder ball and a respective land to which the respective solder ball is soldered, and each perimeter piece includes a respective bar and a respective pad to which the respective bar is soldered.

12. The microelectronic assembly of claim 10 , wherein the perimeter forms a continuous ring around the MEMS device to seal the MEMS device.

13. The microelectronic assembly of claim 10 , wherein the perimeter components have gaps between them so that the perimeter is not continuous around the MEMS device.

14. The microelectronic assembly of claim 1 , further comprising:

a support substrate, the MEMS substrate being placed on the support substrate;

first contact pads on the MEMS substrate outside the perimeter;

second contact pads on the support substrate; and

wirebonding wires connecting each one of the first contact pads with a respective one of the second contact pads.

15. The microelectronic assembly of claim 14 , wherein the perimeter forms a continuous ring around the MEMS device to seal the MEMS device.

16. The microelectronic assembly of claim 14 , wherein the perimeter components form gaps between them so that the perimeter is not continuous around the MEMS device.

17. A microelectronic assembly, comprising:

a first substrate;

a second substrate having a side facing aside of the first substrate;

a plurality of interconnection, elements between the first and second substrates, the interconnection elements connecting the first substrate electrically to the second substrate; and

a plurality of perimeter components, each having opposing portions sealing with the first substrate and the second substrate respectively, the perimeter components forming a perimeter around the interconnection elements wherein the perimeter components have gaps between them so that the perimeter is not continuous around the interconnection elements.

18. The microelectronic assembly of claim 17 , wherein each interconnection element includes a respective solder ball and a respective land to which the respective solder ball is soldered, and each perimeter piece includes a respective bar and a respective pad to which the respective bar is soldered.

19. A microelectronic assembly, comprising:

a MEMS substrate;

a MEMS device on the MEMS substrate, the MEMS device having a MEMS component which is movable relative to the MEMS substrate;

a cover piece having a side over a side of the MEMS substrate on which the MEMS device is located;

a plurality of perimeter components, each having opposing portions sealing with the MEMS substrate and the cover piece respectively, the perimeter components forming a perimeter around the MEMS device; and

a plurality of interconnection elements between the MEMS substrate and the cover piece, the cover piece being a carrier substrate and the interconnection elements connecting the carrier substrate electrically to the MEMS substrate, the interconnection elements being located outside the perimeter.

20. The microelectronic assembly of claim 19 , wherein each interconnection element includes a respective solder ball and a respective land to which the respective solder ball is soldered, and each perimeter piece includes a respective bar and a respective pad to which the respective bar is soldered.

21. The microelectronic assembly of claim 19 , wherein the perimeter forms a continuous ring around the MEMS device to seal the MEMS device.

22. A microelectronic assembly, comprising:

a MEMS substrate;

a MEMS device on the MEMS substrate, the MEMS device having a MEMS component which is movable relative to the MEMS substrate;

a cover piece having a side over a side of the MEMS substrate on which the MEMS device is located;

a plurality of perimeter components, each having opposing portions sealing with the MEMS substrate and the cover piece respectively, the perimeter components forming a perimeter around the MEMS device;

a support substrate, the MEMS substrate being placed on the support substrate;

first contact cads on the MEMS substrate outside the perimeter;

second contact pads on the support substrate; and

wirebonding wires connecting each one of the first contact pads with a respective one of the second contact pads.

23. The microelectronic assembly of claim 22 , wherein the perimeter forms a continuous ring around the MEMS device to seal the MEMS device.

24. The microelectronic assembly of claim 22 , wherein the perimeter components form gaps between them so that the perimeter is not continuous around the MEMS device.

25. A microelectronic assembly, comprising:

a first substrate;

a second substrate having a side facing a side of the first substrate;

a plurality of interconnection elements between the first and second substrates, the interconnection elements connecting the first substrate electrically to the second substrate wherein each interconnection element includes a respective solder ball and a respective land to which the respective solder ball is soldered;

a plurality of perimeter components, each having opposing portions sealing with the first substrate and the second substrate respectively, the perimeter components forming a perimeter around the interconnection elements, and each perimeter component includes a respective bar and a respective pad to which the respective bar is soldered.