Study of plasma-induced damage of porous ultralow-k dielectric films during photoresist stripping

Abstract

Plasma damage of low-k dielectrics during photoresist (PR) stripping in a dual-damascene process is a critical issue in the application of copper/low-k technology for ⩽45nm nodes to increase the signal processing speed of integrated circuit devices. In this article, a detailed and systematic work has been conducted to study the low-k damage on porous methyl silsesquioxane ultralow-k films using various PR strip chemistries and process conditions on a high density plasma reactor. The experimental results obtained from different test methodologies show that the low-k damage generated under fixed process conditions increases in the order of NH3<N2<H2∕N2<H2<O2. Among plasma control parameters, bias power has a very pronounced effect on low-k damage for reducing chemistries due to the acceleration of Si–C bond breaking by ion bombardment. Source power also affects the low-k damage significantly as it controls the ion density and flux to the wafer surface. The pressure effect is more complicated and shows different characteristics for oxidizing and reducing chemistries. The extent of low-k damage depends on the orientation of the wafer surface exposed to the plasma, leading to different sensitivity of the damage to the strip chemistry and process condition. Based on this work, an optimized chemistry and process regime are identified to effectively reduce low-k damage and achieve good strip process performance.

Broadband Dielectric Spectroscopic Characterization of Thermal Stability of Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications

“…The subsequent processing steps increased the substrate temperature and subjected the dielectric materials to both physical and chemical damage, the degree and nature of which depend on the chemistry and conditions used. 51,52 Unlike the remarkable thermal stability of the SOD Bakelitepolymer film (B), the attenuation spectra of both Samples F and E (not shown here) are similar to those of CVD POSS (D); they showed significant changes with storage times at 200°C. In the interest of brevity, we will focus only on the difference spectra to illustrate the chemical changes of the film following the high temperature storage.…”

“…The subsequent processing steps increased the substrate temperature and subjected the dielectric materials to both physical and chemical damage, the degree and nature of which depend on the chemistry and conditions used. 51,52 Unlike the remarkable thermal stability of the SOD Bakelitepolymer film (B), the attenuation spectra of both Samples F and E (not shown here) are …”

Effect of preliminary VUV irradiation on the reactivity of alkyl-doped silicon dioxide layers

“…Plasma treatment is most frequently used [4][5][6][7][8][9][10][11][12]. For instance, it was reported in [11,12] that plasma treatment causes pore closing, which results in a decrease in the reactivity of the layers.…”

Preparation of porous ultra low k films using different sacrificial porogen precursors for 28nM technological node

“…Therefore, the surface modification of the PULK film plays the important role for improving over all performances of the PULK film. In order to reach aim of "pore sealing", the surface of the PULK film is treated by specific plasma or special chemical [20,21].…”