Abstract: A method for estimating molecular nitrogen implantation dosage. The semiconductor wafers are first implanted with various concentration of molecular nitrogen. After implantation, the implanted wafers and a non-implanted wafer are subjected to thermal process to grow oxide layer. The thickness of oxide layer on the wafers with various implantation dosage is measured. Because implanted nitrogen on the wafers suppresses the growth of oxide layer, a suppression ratio is computed from the difference in thickness of the oxide layer between the implanted and non-implanted semiconductor wafers to stand for the thickness variation. Then, a relation between the suppression ratio and the dosages of molecular nitrogen is built. A molecular nitrogen dosage needed to grow a predetermined thickness of oxide layer on a process wafer is computed by inputting the predetermined thickness into the relation.

Abstract: A method for forming tungsten structures over silicon substrates, including the following steps. A silicon substrate is having a patterned dielectric layer formed thereon defining a tungsten structure opening is provided. The silicon substrate is pre-heated to a temperature of from about 430 to 440° C. A Si-rich WSx layer is formed over the patterned dielectric layer, lining the tungsten structure opening. A WSix nucleation layer is formed over the Si-rich WSix layer. A tungsten bulk layer is formed over the WSix nucleation layer, filling the tungsten structure opening, whereby fluorine attack of the Si substrate is minimized.

Abstract: A method for estimating molecular nitrogen implantation dosage. The semiconductor wafers are first implanted with various concentration of molecular nitrogen. After implantation, the implanted wafers and a non-implanted wafer are subjected to thermal process to grow oxide layer. The thickness of oxide layer on the wafers with various implantation dosage is measured. Because implanted nitrogen on the wafers suppresses the growth of oxide layer, a suppression ratio is computed from the difference in thickness of the oxide layer between the implanted and non-implanted semiconductor wafers to stand for the thickness variation. Then, a relation between the suppression ratio and the dosages of molecular nitrogen is built. A molecular nitrogen dosage needed to grow a predetermined thickness of oxide layer on a process wafer is computed by inputting the predetermined thickness into the relation.