Method for characterizing porous low dielectric constant films
View Patent ↗A method and apparatus for determining pore size distribution and/or the presence of at least one killer pore in at least a portion of a porous film deposited upon a substrate are disclosed herein. In one embodiment, there is provided a method for determining pore size distribution comprising: providing the substrate having the film deposited thereupon wherein the film comprises pores and wherein the pores have a first volume; exposing the film to an adsorbate at a temperature and a pressure sufficient to provide condensation of the adsorbate in pores and wherein the pores after the exposing step have a second volume; and measuring the difference between the first and the second volume using a volumetric technique; and calculating the pore size and pore volume using the change in the first and the second volume, the pressure, and a model that relates pressure to pore diameter.
1. A method for determining a presence of at least one killer pore contained within a porous film deposited upon a substrate wherein a pore size of the at least one killer pore is equal to or greater than a reference pore size, the method comprising:
a. providing the substrate having the film deposited thereupon wherein the film comprises pores and wherein the pores have a first volume;
b. exposing the film to an adsorbate at a temperature and a pressure sufficient to provide condensation of the adsorbate in pores and wherein the pores after the exposing step have a second volume;
c. measuring the difference between the first and the second volume;
d. repeating steps b and c wherein the condensed adsorbate has a different density than the previous exposure;
e. calculating the pore size and volume for each exposure using the difference in the first and the second volume, the pressure, and a model that relates pressure to pore diameter and accounts for the change in density of the condensed adsorbate;
f. obtaining a maximum pore size from the distribution; and
g. determining the presence of at least one killer pore by comparing the maximum pore size to a reference pore size.
2. The method of claim 1 wherein the model in the calculating step comprises density function theory.
3. The method of claim 1 wherein the obtaining step comprises using one selected from an absolute pore volume cutoff, a percent pore volume cutoff, and a cutoff pore distribution slope.
4. The method of claim 3 wherein the obtaining step comprises the absolute pore volume cutoff.
5. The method of claim 3 wherein the obtaining step comprises the percent pore volume cutoff.
6. The method of claim 3 wherein the obtaining step comprises a cutoff pore distribution slope.