A method for treating an inter-metal dielectric (IMD) layer to improve a mechanical strength and/or repair plasma etching damage including providing a low-K silicon oxide containing dielectric insulating layer; and carrying out a super critical fluid treatment of the low-K dielectric insulating layer including supercritical CO.sub.2 and a solvent including a silicon bond forming substituent having a bonding energy greater than a Si--H to replace at least a portion of the Si--H bonds with the silicon bond forming substituent.