Semiconductor device having an organic anti-reflective coating (ARC) and method therefor

A method for forming a transistor, comprising:

• providing a semiconductor substrate;
• forming an insulating layer over the semiconductor substrate, wherein the insulating layer is for use as a gate dielectric;
• forming a conductive layer over the insulating layer;
• forming an organic anti-reflective coating (ARC) layer over the conductive layer;
• depositing a silicon oxide cap layer using a organosilane based precursor over the organic ARC layer;
• depositing a photoresist layer over the silicon oxide cap layer;
• patterning the photoresist layer to form a patterned photoresist structure;
• after the patterning, etching the silicon oxide cap and the organic ARC layer using the patterned photoresist structure as a mask;
• thinning the ARC layer to form a thinned organic ARC layer
• etching the conductive using the thinned organic ARC layer as a mask to form a gate from the conductive layer;
• and
• forming a source and a drain in the semiconductor substrate, wherein the source is on a first side of the gate and the drain is on a second side of the gate.