Plasma Dry Etching The Low Dielectric Constant Insulating Materials And Solutions

With the rapid development of high level integration of VLSI circuits, the device dimensions narrows gradually. RC delay became the characteristic dimensions in the device of the main functions of decision devices. RC delay is roughly proportional to the resistivity of the wires and dielectric permittivity. To reduce the resistivity, Copper can be used to replace Aluminum wires. And to reduce the dielectric constants, low dielectric constant of insulating materials, namely low-k materials, must be used. To reduce the dielectric constants of insulation material, the number of key polarization, and the density of material must be reduced. Meanwhile the main problem is low dielectric constant of material mechanical strength greatly reduced. Material composition change will also give dry etching a lot of new problems which have never met before.This paper is based on the experiment of plasma etching low-k material (k value 2.6), explores the approaches to solve the new problems followed with material property changing when plasma dry etching low-k material, such as keeping anisotropic and needed selectivity, avoiding defects, etc. Through the analysis of plasma dry etching low-k material damage mechanism of injury, find out some of the biggest influence defects or process parameters, such as gas species, pressure, RF frequency and power, etc. In the mastery of low-k damage process trend of the above parameters, applies it into plasma etching low-k material (BD) of 40nm Dual Damascene trench etch, achieves the target which is to minimize the low-k damage or defect and meet other process requirement.