Abstract An improved method for the manufacture of semiconductor devices which inhibits the dissolution of substrate silicon from the area of the substrate exposed by a contact window. Two individual layers are disposed on a protective insulative layer such as silicon dioxide which is itself disposed upon a semiconductor wafer. The first layer on the insulating layer is silicon and the second is aluminum. The improvement consists of forming these two layers in specific amounts and with high precision. An aluminum interconnect pattern is then defined using standard photomask and aluminum etch techniques. In a separate step, the silicon is etched using plasma etching techniques. The remaining Al/Si layers are homogenized into an alloy to form the ohmic contacts by heating the wafer in a furnace at high temperatures.
A METHOD FOR FORMING A CONTACT TO REGION IN A EMICONDUCTOR SUBSTRATE THROUGH AN INSULATING LAYER COMPRISING THE STEPS OF. A. FORMING A CONTACT WINDOW IN THE INSULATING LAYER, B. DEPOSITING A LAYER OF SILICON OVER THE INSULATING LAYER C. DEPOSITING A CONDUCTIVE LAYER OVER THE SILICON LAYER, D. DEFINING A PATTERN IN SAID CONDUCTIVE LAYER, E. DEFINING A PATTERN IN SAID SILICON LAYER OF PLASMA ETCHING WITH FREON GAS, AND F. HOMOGENIZING THE REMAINING SILICON AND CONDUCTIVE LAYERS INTO AN ALLOY BY HEATING.
Claim 2
Independent Claim
84 words
A METHOD FOR FORMING A CONTACT TO REGION IN A EMICONDUCTOR SUBSTRATE THROUGH AN INSULATING LAYER COMPRISING THE STEPS OF. A. FORMING A CONTACT WINDOW IN THE INSULATING LAYER, B. DEPOSITING A LAYER OF SILICON OVER THE INSULATING LAYER C. DEPOSITING A CONDUCTIVE LAYER OVER THE SILICON LAYER, D. DEFINING A PATTERN IN SAID CONDUCTIVE LAYER, E. DEFINING A PATTERN IN SAID SILICON LAYER OF PLASMA ETCHING WITH FREON GAS, AND F. HOMOGENIZING THE REMAINING SILICON AND CONDUCTIVE LAYERS INTO AN ALLOY BY HEATING.
Claim 3
Dependent Claim
23 words
The method as defined in claim 1 wherein said insulative layer is silicon dioxide with phosphorus impurities, and said semiconductor substrate is silicon.
Claim 4
Dependent Claim
13 words
The method as defined in claim 1 wherein said conductive layer is aluminum.
Claim 5
Dependent Claim
36 words
The method as defined in claim 3 wherein the thickness of said layer of silicon is 125 + or - 20A and the thickness of said aluminum layer is 1.0 + or - .05 Mu .
Claim 6
Dependent Claim
19 words
The method as defined in claim 3 wherein said conductive layer defines a mask for forming said silicon layer.
Claim 7
Dependent Claim
43 words
The method as defined in claim 1 wherein the amount of silicon in the silicon layer is chosen to provide just enough silicon to saturate the conductive layer at a selected alloy temperature and be completely consumed in the formation of the alloy.
Claim 8
Dependent Claim
30 words
The method as defined in claim 1 wherein said conductive layer is aluminum and wherein said homogenization takes places by heating said remaining layers at 515*C for about 10 minutes.