Planarization properties of hydrogen silsesquioxane (HSQ) influence on CMP

Low dielectric constant materials are now required as intermetallic dielect rics to reduce RC delay in advanced technologies. Hydrogen silsesquioxane ( HSQ) is a spin-on dielectric with a dielectric constant around 3. Local pla narization of HSQ and its impact on the global planarization due to CMP pro cess was studied. Local planarization of HSQ and its impact on the global p lanarization due to CMP process was studied. When lines and spaces are equa l, HSQ shows a good planarization for lines smaller than 20 mu m in this ca se, the HSQ thickness on metal Line is equal to 2500 Angstrom, which is the minimum which can be obtained for this metal thickness and HSQ deposited. For various environments of the metal Line HSQ planarizes better for small lines in a dense zone created by an array of lines or plates of metal. For the CMP process the planarization is good for small lines, as for HSQ but i n an array of lines only. Plates must be totally prohibited for CMP process . Finally, for an intermetal dielectric including HSQ the goal of CMP is no more a local planarization as for gap fill but a large scale intra-die pla narization. (C) 2000 Elsevier Science B.V. All rights reserved.