用于选择性蚀刻和抗蚀剂颗粒去除的加热SC1溶液

A study of the SC1 (NH4OH:H202:H20) solution for use in both resist particulate removal and in selective wet etching of certain films is reported. The ratio of SC1 solutionused for the following tests is 1:2:10. Etch rates for films such as tetraethylorthosilicate oxide, borophosphosilicate glass, nitride, doped polysilicon, and thermal oxide are investigated. Film composition, age of chemicals used, temperature, and composition of chemicals are factors which can influence etch rates of these films.

Wet processes and chemistries for resist and particulate removal are critical in the fabrication of ultra large scale integrated (ULSI) circuits and sequences dependent on Kern's work I,~ are widely used. HCl:H202 (SC2) is used primarily for metallic contamination removal while both piranha (H2SO4:H~O2) and NH4OH:H2Q:H20 (SC1) are considered to be primarily organic contamination cleaning solutions. In this report, etch rate testing is completed at 40, 50, 60, and 80~ Film thickness is measured using a Gaertner ellipsometer. Etch rates are critical if the solution is to be used in a production environment. Results obtained for this report show the feasibility of using the SC1 solution in order to selectively etch certain films common to the semiconductor industry. Heated SC1 has been found to be very effective in etching films such as in situ doped (ISD) polysilicon without damaging the back-side silicon surface. Heated SC1 is also effective in etching filaments of films which may remain after dry etch processes due to anisotropy. Due to the difficulty of removing all resist and organic contamination from the silicon wafer surface, some particulate residue may remain after certain types of processes. Ion implantation is one process which increases the 'hardness' of resist films and, therefore, decreases the efficiency of cleaning techniques often used. This report investigates the effectiveness of SC1 heated to 40, 50, and 80~ for the cleaning of particulate residue resulting from implanted resist. 

The effectiveness of particulate removal is measured using an Estek WIS-8500 particle detection tool. The minimum resolution for the results reported is 0.2 ~m on bare silicon wafers. Particles of size 0.2 ~m and larger are detected and either the total number added or the delta value between pre cleaning and post cleaning are reported, depending on the process. The resist coating, ion implantation or plasma etching, and ashing steps are used to generate particles typically found in semiconductor processing using process sequences and parameters which would be used for 0.5 ~m DRAM fabrication.