Fluorine Diffusion from Fluorosilicate Glass

Abstract

A stable fluorosilicate glass (FSG) has been fabricated from the chemical vapor deposition of SiF4/tetraethylorthosilicate (TEOS)/02 and C2FjrEOS/02. Films were subjected to a temperature and humidity stress for water absorption studies and were thermally stressed for fluorine diffusion studies. Fourier transform infrared spectrometry (FTIR) and secondary ion mass spectrometry (SIMS) indicate films produced from SiF4 absorb less water and diffuse less fluorine into SIO than films produced from C2F6. The activation energies of fluorine diffusion were calculated to be 1.00 and 0.82 eV for SiF4 and C2F9 FSG, respectively.

Study of FSG/SiO/sub 2/ double interlayer conditions to prevent Al wiring delamination for sub-0.18-μm device integration

“…Postannealing and increasing the deposition temperature of the FSG film, which are recommended for reducing F diffusion in [4], displayed no suppression of F incorporation at Ti-SiO in this experiment. This was because the deposition temperature was lower and the postannealing time was shorter than those in [4].…”

“…This was because the deposition temperature was lower and the postannealing time was shorter than those in [4]. Also, less unstable SiF ( ) was generated at 4.4 at.% of F in the FSG used in this study rather than at the higher F content used in [4].…”

“…An F content exceeding 4 at.%, though, gen- erates an unstable SiF ( ), which induces water absorption and degrades the film adhesion with the metal layer [3], [4]. In order to solve these problems, a stack IMD layer structure consisting of FSG and capping SiO film has been proposed [5].…”

“…From this point, prudent measures need to be taken to cope with Al wiring delamination. Several studies suggested that titanium fluoride formed by the reaction of the Ti barrier layer and F atoms released from the FSG film caused metal line delamination [4], [8]- [11]. However, a detailed investigation has not been conducted to explain the clear mechanism of delamination.…”

“…3(b) that the Al metal line separated from the SiO film at the Ti-TiN barrier. The degradation of metal adhesion has been reported to be attributable to some intermetallic compound generated by fluorine atoms and barrier metals [4], [8]- [11]. For Al wiring delamination, it can be assumed that the interaction of the Ti layer and fluorine penetrating through the SiO film caused the metal delamination.…”