Effect of terminal methyl group concentration on critical properties and plasma resistance of organosilicate low-k dielectrics

Abstract

Surfactant-templated porous organosilicate glass low-k films have been deposited by using a tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS) mixture with different ratios and Brij® 30 surfactant. The deposited films contain different concentrations of terminal methyl groups that are proportional to the MTEOS concentration. Increasing the methyl group concentration by changing the TEOS/MTEOS ratio decreases the open porosity, k-value, and Young's modulus and increases the mean pore radius, although the template concentration was kept constant. The plasma etch rate well correlates with the number of fluorine atoms penetrated into pores. Plasma damage by fluorine radicals depends on the carbon concentration in the films. It can be reduced by 60% when the carbon concentration in the films exceeds 10 at. % as measured by XPS (the films deposited with the TEOS/MTEOS ratio of 40/60). Damage to the dielectrics associated with exposure to vacuum ultraviolet photons is reduced by more than 70% for the same samples.

Modification of Porous Ultralow-k Film by Vacuum Ultraviolet Emission

“…Figure a shows relative changes in the integral of the following peaks: Si-CH 3 peak at 1275 cm –1 , terminal C–H 2 peaks at ∼2930 cm –1 and ∼2855 cm –1 , ∼1350–1380 cm –1 peaks from methylene bridges and a broad water peak ∼3000–3700 cm –1 .…”

“…The carbon compounds in the range 2800−3000 cm −1 are represented by terminal CH 3 (also seen at 1275 cm −1 ) and CH 2 groups. Figure 3a shows relative changes in the integral of the following peaks: Si-CH 3 peak at 1275 cm −1 , terminal C−H 2 peaks at ∼2930 cm −1 and ∼2855 cm −1 , 50 ∼1350−1380 cm −1 peaks from methylene bridges 51 and a broad water peak ∼3000−3700 cm −1 .…”

Selective Pulsed Chemical Vapor Deposition of Water-Free TiO2/Al2O3 and HfO2/Al2O3 Nanolaminates on Si and SiO2 in Preference to SiCOH

“…For the Cu/SiCOH samples received from Applied Materials, the pitch size was ∼90 nm and the average linewidth was ∼45 nm. Patterned SiCOH surface methyl groups can be damaged by plasma etching, UV lithrography, and even diffusion barrier sputtering processes which result in the formation of Si–H, Si–OH, and Si dangling bonds on the surface. − Similar to the silylation repair (forming a Si–O–CH 3 bond) demonstrated by Oszinda et al, passivation (damage repair) was performed using a proprietary process from Applied Materials to restore surface methyl concentration . Degreased SiCOH samples were also passivated by this method as controls.…”

Evaluation of Mechanical Properties of Porous OSG Films by PFQNM AFM and Benchmarking with Traditional Instrumentation

“…The CH 3 /Si ratio changed from 0 to 1 on changing the TEOS/MTEOS ratio, and porosity is defined by the porogen concentration. Normally, the methyl groups concentration must be carefully optimized . It should be large enough to provide hydrophobic properties while still maintaining sufficient mechanical properties and chemical/plasma resistance.…”

“…Normally, the methyl groups concentration must be carefully optimized. 45 It should be large enough to provide hydrophobic properties while still maintaining sufficient mechanical properties and chemical/plasma resistance. More detailed information can be found in the Supporting Information.…”