PROCESS CHARACTERISTICS FOR SUBATMOSPHERIC CHEMICAL-VAPOR-DEPOSITED BOROPHOSPHOSILICATE GLASS AND EFFECT OF CARRIER GAS

Borophosphosilicate glass (BPSG) has been widely used as a premetal di electric to achieve excellent gap fill and planarization due to its re flow capability. In this paper, we present some characterizations of s ubatmospheric chemically vapor deposited BPSG, aiming at developing a mechanistic understanding of this process. By comparing the effect of controlling variables on the film properties of BPSG and undoped silic on oxide, we conclude that this deposition process is controlled by th e gas-phase diffusion of the reaction intermediates on the Si substrat e. Therefore, chamber pressure and susceptor spacing are the two major process variables other than the reactant flows. The helium carrier g as process shows better film properties in terms of high deposition ra te, smooth film, and good reflow capability.