Effect of bridging groups of precursors on modulus improvement in plasma co-polymerized low-k films

Abstract

We have demonstrated that the mechanical strength of organic silica low-k films can be enhanced by introducing a reinforcement monomer in a matrix monomer under plasma excitation. The modulus improvement mechanism was investigated by analyzing the film structure. Pyrolysis gas chromatography /mass spectrometry (Py-GUMS) revealed incorporation of a reinforcement monomer in the matrix through co-polymerization reactions. Compositional analysis of the films showed that the extent of reinforcement is associated with co-polymerization ratio or the monomer content in the film. It is also indicated that the modulus enhancement depends on the content of 3-dimensional aromatic bridged structure, which is affected by the chemical structure of the reinforcement monomers.

Non‐Porous Low‐k Dielectric Films Based on a New Structural Amorphous Fluoropolymer

“…In conclusion, we have designed and synthesized a new amorphous fluoropolymer ( PFN ), which shows a dielectric constant of 2.33 with a dielectric loss less than 1.2 × 10 −3 at 30 MHz. Moreover, the polymer film shows k values below 2.5 in the range from 5 to 30 MHz; such dielectric constants are much lower than those of previously reported polymeric low‐ k materials such as polyimides,1d, 19 SiLK,20 and benzocyclobutene (BCB)‐based polymers 21. In comparison with porous low k materials, PFN shows a higher modulus and bonding strength, which renders it suitable for the application in ULSI circuits.…”

“…Moreover, the polymer fi lm shows k values below 2.5 in the range from 5 to 30 MHz; such dielectric constants are much lower than those of previously reported polymeric low-k materials such as polyimides, [ 1d , 19 ] SiLK, [ 20 ] and benzocyclobutene (BCB)-based polymers. [ 21 ] In comparison with porous low k materials, PFN shows a higher modulus and bonding strength, which renders it suitable for the application in ULSI circuits. …”

Low Dielectric Constant Materials

“…In this review, we have been very selective in our discussions of low- k spin-on organic polymer candidates and have restricted our discussion to those materials that historically presented the best opportunity for success. In addition to those presented as potential spin-on solutions for the k = 2.6−3.2 dielectric range, there were also studies in vapor-deposited polymers: parylenes − and polynaphthalenes, , silicon-substituted polyimides, ,− polyquinoxalines, quinolines, ,, norbornenes, , benzocyclobutenes, ,,, carbon-bridged benzocyclobutene hybrids, indanes, , perfluorocyclobutanes, ,, and others, the details of which appear in the literature and in referenced reviews.…”

An Organic Low-k Film Deposited by Plasma-Enhanced Copolymerization

“…3 The effects of copolymerization of the skeleton monomer and various modification monomers on film properties were investigated for the purposes of deposition acceleration, mechanical reinforcement, and reduction of the dielectric constant. [3][4][5] In this study, we focused on development of organic skeleton monomers for the PCP technology. Properties of the PCP films can be controlled by precursors because most of the original structure of the precursors could be preserved owing to the low plasma energy of the PCP process.…”