Void Formation in Phosphosilicate Glass Film with Heat‐Treatment in H 2 Atmosphere

Abstract

The void formation process and phosphorus behavior in phosphosilicate glass film deposited by chemical vapor deposition techniques were investigated. The films were heat‐treated three times, first in atmosphere for densification, then in or atmosphere, and after that in atmosphere. It was found that (i) void formation takes place with the third heat‐treatment in atmosphere, (ii) with the second heat‐treatment in atmosphere, absorbance of P=O band at 1330 cm−1decreases and absorbance of band at 1250 cm−1 increases, but further absorbance change does not take place with the third heat‐treatment. The gain in absorbance of the band at 1250 cm−1 is proportional to the loss in absorbance of the P=O band at 1330 cm−1. The quantity of phosphorus products formed with heat‐treatment in atmosphere was estimated from the absorbance change of the P=O band at 1330 cm−1. Comparing the quantity of the phosphorus products with the void size and number, it was proposed that the phosphorus products are gaseous species at high temperature, and the quantity of the gaseous species determines the product of the void number in the PSG film and square of the void size.