Plasma processing of low-k dielectrics

Abstract

This paper presents an in-depth overview of the present status and novel developments in the field of plasma processing of low dielectric constant (low-k) materials developed for advanced interconnects in ULSI technology. The paper summarizes the major achievements accomplished during the last 10 years. It includes analysis of advanced experimental techniques that have been used, which are most appropriate for low-k patterning and resist strip, selection of chemistries, patterning strategies, masking materials, analytical techniques, and challenges appearing during the integration. Detailed discussions are devoted to the etch mechanisms of low-k materials and their degradation during the plasma processing. The problem of k-value degradation (plasma damage) is a key issue for the integration, and it is becoming more difficult and challenging as the dielectric constant of low-k materials scales down. Results obtained with new experimental methods, like the small gap technique and multi-beams systems with separated sources of ions, vacuum ultraviolet light, and radicals, are discussed in detail. The methods allowing reduction of plasma damage and restoration of dielectric properties of damaged low-k materials are also discussed.

Influence of Substrate Materials on Deposition of Plasma-polymerized SiO:CH Particles

“…Silica materials with organic functional groups (SiO:CH) has attracted much attention because of its hydrophobicity, flexible bonding states, and low dielectric constant for the applications such as water-repellent surfaces [1][2], gas-barrier coatings [3][4], and insulating layers in microelectronic devices [5][6]. These properties can be improved when the SiO:CH films have microstructures with appropriate size and shapes.…”

Plasma-polymerized Particles from Organosilane Molecules and Microstructure of Their Deposits

“…Recently, silica-based films with organic functional groups (SiO:CH) deposited by PECVD have been intensively studied for various applications such as low-k layers in semiconductor devices [1], gas barrier films [2][3], water-repellent surfaces [4][5], etc. The PECVD with organosilicon reactants can synthesize not only uniform films but also microparticles at relatively higher pressure due to polymerization of the reactants in plasma phases [6][7][8][9][10].…”

Cu passivation for integration of gap-filling ultralow-k dielectrics

“…2,3 Using chemical-vapor co-deposition of matrix and porogen precursors, continuous k value reduction is achieved by increasing the porogen/matrix ratio so as to generate higher open porosity. However, larger porosity is generally accompanied by an increased pore size, 4 leading to poor mechanical integrity and poor resistance to plasma induced damage, 5 lowered chemical resistance (wet clean), 6 deep metal penetration during barrier deposition 7,8 and enhanced slurry residues after Cu chemical mechanical polishing. 9,10 As a result, the "effective" k-values for integrated inter-metal dielectrics are significantly higher than those of pristine materials.…”