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AssigneeMotorola, Inc.
InventorsMerrill Roe Hunt, Christopher Angelos Ladas, Sal Thomas Mastroianni
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A double master mask process for fabricating semiconductor integrated circuits is provided in which selectively etchable dielectric layers and ion implanted resistors are used to form dense integrated circuits with a minimum number of critical alignments. A first silicon dioxide silicon nitride layer used in conjunction with a first master photomask defines a base region and an isolation region which are self-aligned with respect to each other and with respect to resistor contact regions. After isolation and base diffusion, the first oxide/nitride layer is stripped away and a second oxide/nitride layer is grown. Using a photoresist mask, a predeposition layer for the resistor is then formed using ion implantation through the oxide/nitride layers. A second master photomask allows the formation of collector and emitter regions and base and resistor contact which are self-aligned with respect to each other. The diffusion cycle used to form the collector contact and emitter regions simultaneously anneals the ion implanted resistor region to form a high value resistor of closely controlled tolerances. In conjunction with the use of the first master mask, a base region and isolation region which are self-aligned with respect to each other are formed through the use of a " base washout" process which maintains self-alignment without the use of additional process steps.
A self-aligned method of manufacturing integrated circuits comprising the steps of:
A self-aligned method of manufacturing integrated circuits comprising the steps of:
Dependencies are inferred from the claim text.