High aspect ratio etch with combination mask

摘要

A method for etching features in a stack is provided. A combination hardmask is formed by forming a first hardmask layer comprising carbon or silicon oxide over the stack, forming a second hardmask layer comprising metal over the first hardmask layer, and patterning the first and second hardmask layers. The stack is etched through the combination hardmask.

主权项

1. A method for etching features in a stack, comprising:
forming a combination hardmask, comprising;
forming a first hardmask layer comprising carbon or silicon oxide over the stack;forming a second hardmask layer comprising metal over the first hardmask layer;forming a third hardmask layer comprising carbon or silicon oxide over the second hardmask layer, andforming a fourth hardmask layer comprising metal over the third hardmask layer;etching the fourth hardmask layer, comprising:
flowing a fourth hardmask layer etch gas comprising a halogen component; andforming the fourth hardmask layer etch gas into a plasma; andstopping the flow of the fourth; andetching the third hardmask layer, comprising:
flowing a third hardmask layer etch gas comprising oxygen and at least one of COS or SO2;forming the first hardmask layer etch gas into a plasma; andstopping the flow of the first hardmask layer etch gas;patterning the first and second hardmask layers; and etching the stack through the combination hardmask.