US5111276A — Thick bus metallization interconnect structure to…

Claim 1

Independent Claim 189 words

A metallization structure for a horizontally extending power bus region and horizontally extending interconnect lines in an integrated circuit comprising: a semiconductor substrate having circuit elements formed therein; a conductive bus region; horizontally extending conductive interconnect lines coupled to said circuit elements and to said power bus region for transmitting power from said power bus region to said circuit elements; said horizontally extending power bus region and said horizontally extending interconnect lines being formed of a first horizontally extending conductive layer of a first predetermined thickness and insulated from said substrate except for the connections with said elements; said power bus region further being formed of a second horizontally extending conductive layer disposed upon and in physical contact with an upper surface of and in electrical contact with selected portions of said first horizontally extending conductive layer, said second horizontally extending conductive layer having a second predetermined thickness; and, said metallization structure thereby defining a power bus region with a thickness greater than the thickness of said interconnect lines wherein said first horizontally extending conductive layer is integral both to said interconnect lines and to said power bus region.

Claim 2

Dependent Claim 189 words

A metallization structure for a horizontally extending power bus region and horizontally extending interconnect lines in an integrated circuit comprising: a semiconductor substrate having circuit elements formed therein; a conductive bus region; horizontally extending conductive interconnect lines coupled to said circuit elements and to said power bus region for transmitting power from said power bus region to said circuit elements; said horizontally extending power bus region and said horizontally extending interconnect lines being formed of a first horizontally extending conductive layer of a first predetermined thickness and insulated from said substrate except for the connections with said elements; said power bus region further being formed of a second horizontally extending conductive layer disposed upon and in physical contact with an upper surface of and in electrical contact with selected portions of said first horizontally extending conductive layer, said second horizontally extending conductive layer having a second predetermined thickness; and, said metallization structure thereby defining a power bus region with a thickness greater than the thickness of said interconnect lines wherein said first horizontally extending conductive layer is integral both to said interconnect lines and to said power bus region.

Claim 3

Dependent Claim 27 words

A structure as defined in claim 1 further comprising a third conductive layer interposed between said conductive power bus and said circuit elements formed on said substrate.

Claim 4

Dependent Claim 24 words

A structure as defined in claim 1 further comprising a third conductive layer formed above said power bus and in electrical contact with it.

Claim 5

Dependent Claim 42 words

A structure as defined in claim 1 wherein said first and second conductive layers of said power bus are self aligned such that there is never any mask registration error overlap between said first and second conductive layers of said power bus.

Claim 6

Dependent Claim 83 words

The structure of claim 4 wherein said first conductive layer is chosen from a first class of conductive materials which are subject to etching by a first etching process that will not etch the material of said second layer and said second conductive layer is chosen from a second class of conductive materials not subject to etching by the first etching process and which are subject to etching by a second etching process that will not etch the material of said first layer.

Claim 7

Dependent Claim 48 words

The structure of claim 5 wherein said first conductive layer is chosen from the group comprising aluminum, tungsten or silicide and said second layer is one of the other materials in this group which is not subject to etching by the process chosen to etch said first layer.

Claim 8

Dependent Claim 19 words

The structure of claim 5 wherein said first conductive layer is aluminum and the second conductive layer is tungsten.

Claim 9

Dependent Claim 19 words

The structure of claim 5 wherein said first conductive layer is aluminum and the second conductive layer is silicide.

Claim 10

Dependent Claim 81 words

The structure of claim 1 wherein said first conductive layer is chosen from a first class of conductive materials which are subject to etching by a first etching process that will not etch the material of said second layer and said second conductive layer is chosen from a second class of conductive materials not subject to etching by the first etching process and which are subject to etching by a second etching process that will not etch said first conductive layer.

Claim 11

Dependent Claim 38 words

The structure of claim 1 wherein said second layer forming said bus is deposited to have an upper surface higher above said substrate than the portions of the upper surface of said first layer forming said interconnect lines.

Claim 12

Dependent Claim 28 words

The structure of claim 10 wherein the portions of said first layer forming said interconnect lines and said bus are disposed substantially the same height above said substrate.

Claim 13

Dependent Claim 25 words

The structure of claim 1 further comprising a third conductive layer interposed between said conductive power bus and said circuit elements formed on said substrate.

Claim 14

Dependent Claim 24 words

The structure as defined in claim 1 further comprising a third conductive layer formed above said power bus and in electrical contact with it.

Claim 15

Dependent Claim 43 words

The structure of claim 1 wherein said first and second conductive layers of said power bus are self aligned such that there is never any mask registration error overlap at the edges of said first and second conductive layers of said power bus.

Claim 16

Dependent Claim 86 words

The structure of claim 4 wherein said first conductive layer is chosen from a first class of conductive materials which are subject to etching by a first plasma etching process that will not etch the material of said second layer and said second conductive material is chosen from a second class of conductive materials not subject to etching by the first plasma etching process and which are subject to etching by a second plasma etching process that will not etch the material of the first layer.

Claim 17

Dependent Claim 84 words

The structure of claim 1 wherein said first conductive layer is chosen from a first class of conductive materials which are subject to etching by a first plasma etching process that will not etch the material of said second layer and said second conductive layer is chosen from a second class of conductive materials not subject to etching by the first plasma etching process and which are subject to etching by a second plasma etching process that will not etch the first conductive layer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-05-05	1995-11-04	1996-05-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-05-05	1999-11-04	2000-05-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-05-05	2003-11-04	2004-05-05	$7700.00	Window Closed / Lapsed

Thick bus metallization interconnect structure to reduce bus area

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