Preventing breakage of long metal signal conductors on semiconductor substrates
An apparatus includes a volume of insulator disposed over a top surface of a semiconductor substrate, a tube of soft dielectric, and a metal conductor. The insulator has a hardness of more than approximately three gigapascals (gPa) and the soft dielectric has a hardness of less than three gPa. The tube of soft dielectric and the metal conductor are both embedded within the volume of insulator. The tube defines a central volume and the metal conductor extends in a direction through the central volume for a distance of at least one inch. The metal conductor is encircled by the soft dielectric when the apparatus is viewed in a cross-sectional plane perpendicular to the direction. The metal conductor may include a plurality of bend portions. The metal conductor does not break when the apparatus is temperature cycled over a range from zero to eighty five degrees Celsius.
1. An apparatus, comprising:
a volume of an insulator disposed over a top surface of a semiconductor substrate, wherein the insulator has a hardness of more than approximately three gigaPascals (gPa);
a tube of soft dielectric embedded within the volume of insulator, the tube defining a central volume, wherein the soft dielectric has a hardness of less than three gPa; and
a metal conductor that extends in a direction through the central volume for a distance of at least one inch, wherein the metal conductor is encircled by the soft dielectric when the apparatus is viewed in a cross-sectional plane perpendicular to the direction, wherein the metal conductor includes a plurality of bend portions.
2. The apparatus of claim 1 , wherein there is at least one bend portion in each ten millimeter stretch of the metal conductor.
3. The apparatus of claim 1 , wherein the metal conductor expands due to increased temperature such that the soft dielectric gets compressed at a plurality of locations that correspond to the plurality of bend portions.
4. The apparatus of claim 1 , wherein the insulator is silicon dioxide.
5. The apparatus of claim 1 , wherein the tube has a rectangular outer peripheral edge when viewed in the cross-sectional plane.
6. The apparatus of claim 1 , wherein a top surface of the volume of insulator extends in a surface plane, and wherein the metal conductor bends in a dimension parallel to the surface plane, and wherein each one of the plurality of bend portions has a bend angle of more than ninety degrees.
7. The apparatus of claim 1 , wherein a top surface of the volume of insulator extends in a surface plane, and wherein the metal conductor bends in a dimension perpendicular to the surface plane.
8. The apparatus of claim 7 , wherein the metal conductor has a sine wave shape.
9. The apparatus of claim 7 , wherein the metal conductor has a cork-screw shape.
10. The apparatus of claim 9 , wherein the soft dielectric is a low-k dielectric taken from the group consisting of: Aerogel, fluorinated silicon glass (FSG), aromatic hydrocarbon-based dielectric material (SilK), and fluorinated poly (arylene ether) (FLARE).
11. The apparatus of claim 1 , wherein the metal conductor does not break when the temperature of the metal conductor is temperature cycled over a range from zero to eighty-five degrees Celsius.
12. The apparatus of claim 1 , wherein the metal conductor conducts an electrical signal.
13. The apparatus of claim 1 , further comprising:
a first pad; and
a second pad, wherein the metal conductor is coupled to the first pad and the second pad.
14. The apparatus of claim 13 , wherein an electrical signal is communicated from the first pad, through the metal conductor, to the second pad.
15. The apparatus of claim 13 , wherein the first pad is a portion of a conductive connector strip.
16. The apparatus of claim 13 , wherein the second pad is a portion of a Field Programmable Gate Array (FPGA).
17. The apparatus of claim 1 , further comprising:
a Field Programmable Gate Array (FPGA) chip, wherein the FPGA chip includes a first pad; and
a conductive connector strip, wherein the conductive connector strip includes a second pad, and wherein the metal conductor is coupled to the first pad and the second pad.
18. The apparatus of claim 17 , wherein an electrical signal is communicated from the first pad of the FPGA, through the metal conductor, to the second pad of the conductive connector strip.
19. The apparatus of claim 1 , wherein the volume of the insulator disposed over the top surface of the semiconductor substrate, the tube of soft dielectric embedded within the volume of insulator, and the metal conductor comprise a means for conducting a signal.
20. The apparatus of claim 19 , wherein the means does not break when the temperature of the means is temperature cycled over a range from zero to eighty-five degrees Celsius.