Process kit and wafer temperature effects on dielectric etch rate and uniformity of electrostatic chuck

Abstract

Articles you may be interested inEffect of wafer bow on electrostatic chucking and back side gas cooling High-temperature electrostatic chuck for nonvolatile materials dry etch Etch rate and uniformity are two basic indicators of how rf power is coupled into the wafer. In reactive ion etch of dielectric layers, wafer temperature also appears as a key parameter, due to the innate deposition. When electrostatic chuck is introduced, we have to study and control both rf coupling and wafer temperature to maximize etch rate and minimize nonuniformity. We first review the basics of the electrostatic chuck ͑e-chuck͒ design and operation, and check them against Applied Materials' polyimide monopolar e-chuck. Then a simple circuit model is developed and fitted to the experimental results. The model says to have higher etch rate, one needs to couple more energy through the wafer center. This is achieved by using a thicker insulating process kit with low dielectric constant. The uniformity study shows for a given wafer, its etch rate variation across the wafer can be divided into three sections-center, B-field corner, and very edge of the wafer, and each section is controlled by a key parameter. By optimizing these parameters, we are able to increase the etch rate and decrease its nonuniformity to 1.5% ͑1, 3 mm edge exclusion͒. Finally, wafer temperatures of both center and edge are studied and the delta between center and edge is reduced to ϳ6°C, and spin-on-glass etch rate nonuniformity is reduced to 1 of 1.88%.

Enhanced temperature uniformity of electrostatic chuck: ceramic surface contact ratio and backside gas pressure

“…Wafer-temperature control is a key parameter deeply related to process quality as well as chip production yield. [1][2][3] A small variation in a local temperature on the wafer-in-process causes a large deviation in the deposition and etching processes. [4][5][6][7] Thermal energy generated by atomic collision during the process was regarded the most suspicious reason, and it has been reduced by controlling temperature through an electrostatic chuck (ESC).…”

Fabrication of Planar Heating Chuck Using Nichrome Thin Film as Heating Element for PECVD Equipment

“…The increasing demand for memory devices with expanded storage capacity [4] has driven the need for highly stacked uniform thin films [5], which require the precise control of the temperature of wafers during the PECVD process. Because temperature uniformity and the ramping-up/-down rata of the PECVD equipment critically determine yield and fabrication throughput [6][7][8][9][10][11], they are the main evaluation criteria of the capability of PECVD equipment and wafer chucks (or heaters).…”

Prediction of residual clamping force for Coulomb type and Johnsen–Rahbek type of bipolar electrostatic chucks

“…In particular, an electrostatic chuck is an indispensable component for a dry etcher or chemical-vapor deposition (CVD) apparatus. It is clear that the clamping force is one of the most important factors influencing the effectiveness of an electrostatic chuck, 1–5 which can directly or indirectly influence other key parameters including wafer temperature, wafer flatness, and so on.…”