METHODS OF MAKING A MONOLITHIC MICROWAVE INTEGRATED CIRCUIT
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Accused Products
Abstract
Low Q associated with passive components of monolithic integrated circuits (ICs) when operated at microwave frequencies can be avoided or mitigated using high resistivity (e.g., ≧100 Ohm-cm) semiconductor substrates and lower resistance inductors for the IC. This eliminates significant in-substrate electromagnetic coupling losses from planar inductors and interconnections overlying the substrate. The active transistor(s) are formed in the substrate proximate the front face. Planar capacitors are also formed over the front face (63) of the substrate. Various terminals of the transistor(s), capacitor(s) and inductor(s) are coupled to a ground plane on the rear face of the substrate using through-substrate-vias to minimize parasitic resistance. Parasitic resistance associated with the planar inductors and heavy current carrying conductors is minimized by placing them on the outer surface of the IC where they can be made substantially thicker and of lower resistance. The result is a monolithic microwave IC previously unobtainable.
5 Citations
36 Claims
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1-9. -9. (canceled)
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10. A method for forming a monolithic microwave integrated circuit having an input terminal, an output terminal and a reference terminal, the method comprising:
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providing a high resistivity initial semiconductor substrate having an initial thickness between a first surface and an initial second surface; forming at least one transistor in the initial semiconductor substrate with input terminal, output terminal and reference terminal proximate the first surface; forming one or more conductor filled substrate vias extending into the initial semiconductor substrate through the first surface; forming one or more planar capacitors over the first surface of the initial substrate, each capacitor having first and second terminals; forming one or more planar inductors over the first surface of the initial substrate, wherein the first terminal or the second terminal of the one or more planar capacitors is coupled to a first terminal or a second terminal of the one or more planar inductors wherein other terminals of the one or more planar inductors are coupled to through substrate vias, to one or more terminals of the transistor or to one or more terminals of the microwave integrated circuit; reducing the initial thickness, thereby creating a new rear surface of a thinned substrate on which inner ends of the substrate vias are exposed; and applying a conductor to the new rear surface of the thinned substrate so that the exposed inner ends of the substrate vias are electrically connected to the conductor. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17-20. -20. (canceled)
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21. A method for forming a monolithic microwave integrated circuit, the method comprising:
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forming portions of a transistor at a front surface of a semiconductor substrate, wherein the transistor has a doped common region, and wherein the semiconductor substrate has a bulk resistivity equal to or greater than 100 Ohm-cm; forming multiple conductive through-substrate vias (TSVs) extending from the front surface of the semiconductor substrate at least partially through the semiconductor substrate; forming electrical interconnections overlying the front surface of the semiconductor substrate to electrically couple the transistor with at least some of the multiple conductive TSVs; and forming a reference node supported by a rear surface of the semiconductor substrate and electrically coupled with at least some of the multiple conductive TSVs. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for forming a monolithic microwave integrated circuit, the method comprising:
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forming a Laterally-Diffused-Metal-Oxide-Semiconductor (LDMOS) transistor at a front surface of a semiconductor substrate, wherein the LDMOS transistor has a gate, a drain region, and a source region, and wherein the semiconductor substrate has a bulk resistivity equal to or greater than 100 Ohm-cm; forming multiple conductive through-substrate vias (TSVs) extending from the front surface of the semiconductor substrate to a rear surface of the semiconductor substrate; forming electrical interconnections overlying the front surface of the semiconductor substrate to electrically couple the transistor with at least some of the multiple conductive TSVs; and forming a reference node supported by the rear surface of the semiconductor substrate and electrically coupled with at least some of the multiple conductive TSVs. - View Dependent Claims (31, 32, 33)
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34. A method for forming a monolithic microwave integrated circuit, the method comprising:
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forming a transistor in a semiconductor substrate, wherein the transistor includes a doped common region; forming a first dielectric layer over a front surface of the semiconductor substrate; forming a first through-substrate via (“
TSV”
) extending through the first dielectric layer and the semiconductor substrate, wherein a region of the semiconductor substrate through which the first TSV passes has a bulk resistivity equal to or greater than 1000 Ohm-cm;forming an interlayer via in the first dielectric layer, the first TSV electrically coupled to the doped common region of the transistor through the interlayer via; monolithically forming a passive component over the front surface of the semiconductor substrate; forming planar interconnections overlying the front surface of the semiconductor substrate and coupling the transistor and the passive component; and forming a reference node supported by the rear surface of the semiconductor substrate, which is electrically coupled to the transistor through the first TSV. - View Dependent Claims (35, 36)
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Specification