Toward Successful Integration of Porous Low-k Materials: Strategies Addressing Plasma Damage

Abstract

The increasing sensitivity of porous low dielectric constant materials to process damage constitutes a major roadblock to their implementation in back-end-of-the-line (BEOL) wiring structures for advanced technology nodes. In the early 2000s and in anticipation to future low-k related integration challenges, the semiconductor industry started to investigate the possibility to repair or prevent this damage. It is remarkable that the most disruptive solutions proposed today are inspired from the work initiated more than 10 years ago. In this review we first describe the accepted mechanisms for plasma damage, followed by a quick summary of the methods used to quantify its extent on both blanket films and patterned structures. We then report on the past and current strategies developed to mitigate the plasma damage of porous, low-k materials during damascene integration processes.

Role of Carbon Bridge Length of Organosilicate Precursors on the Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics

“…The incomplete dissociation of the side ethyl group in carbon bridge precursor may also contribution of the intensity of peak at 1470 cm −1 . The dual precursors layer showed higher intensity of peaks at 1380, 1420, or 1430 cm −1 , which refer to Si–CH 2 –Si, Si–(CH 2 ) 2 –Si or Si–(CH 2 ) 6 –Si peaks . The carbon bridge structure are very sensitive to oxidative plasma environment, which was proved in our previous paper .…”

Grignard condensation routes to 1,3‐disilacyclobutane‐containing cyclolinear polycarbosilanes

“…The most important requirements for low‐ k materials are resistance to plasma damage and high mechanical strength . PB‐CLPCS contains a high percentage of carbon atoms and should therefore exhibit good resistance to plasma damage .…”

The efficacy of post porosity plasma protection against vacuum-ultraviolet damage in porous low-k materials

“…Impact of v-UV photons on a unfilled k 5 2.0 low-k material Following pristine low-k characterization, the coupons that were exposed to v-UV photons only (MgF 2 cover window) were also analyzed by XRR, which detects changes in density and thickness that are indicative of plasma damage. 14 The results are summarized in Table II. In the case of the fluorocarbon plasma, the sample does not display any significant difference in density, thickness, or scan shape compared to the equivalent pristine material, 23 indicating that the porous dielectric material was not damaged by the fluorocarbon plasma v-UV photons. It is worth mentioning that the most intense v-UV emission lines, which come from Ar (104-106 nm) and H (120 nm), were cut-off by the MgF 2 window.…”

“…[10][11][12][13] Over the past 15 years, a lot of efforts have been devised to either prevent or mitigate plasma damage. 14 Among them, post-porosity plasma protection (P4) is the only strategy that takes advantage of the increasing porosity with decreasing dielectric constant in low-k materials. [15][16][17] The P4 efficacy has already been demonstrated on a wide range of spin-on and PECVD dielectric materials on both blanket and patterned structures.…”