PROJECT TITLE :

Experimental Study on Etching Characteristics of a Spin-Etching Method

ABSTRACT:

In this paper, a spin-etching methodology is proposed for wafer thinning using a mixture of hydrofluoric, nitric, and acetic acids (HNA resolution), and experimental studies are conducted. Within the spin-etching equipment, the silicon wafer was rotated in a very Teflon bath filled with HNA solution. The etch rate of HNA spin-etching can be determined by mixture ratio; mass transfer, each through and in boundary layer; and warmth transfer. When the Reynolds variety of the flow on the rotating disk is below $1.8 times 10^5$ , the flow is in the laminar region, and also the boundary layer thickness and convective heat transfer coefficient do not vary with radius at the same rotational speed. During this study, the silicon wafer was rotated at <60 rpm, at which the flow was within the laminar region. Nevertheless, the local etch rate varied with the radial position. To analyze spin-etching characteristics of the silicon wafer rotated within the laminar region, experimental studies on etch rate and uniformity of etch of six-in silicon wafers as the rotational speed was varied were dispensed with varied HNA mixture ratios. [2015-0031]