Bryan Pu

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

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‐chuck) 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 param...

MxP+: A new dielectric etcher with enabling technology, high productivity, and low cost‐of‐consumables

Dielectric etch accounts for more than half of all the dry etches used in integrated circuit (IC) fabrication, and plays a very important role in fulfilling strict requirements of volume‐manufacturing of IC circuits whose feature size is progressively decreasing. The challenge of meeting volume manufacture requirements is what MxP+ has achieved through a series of hardware and process innovations. By Pareto analysis of the wet clean time of the MxP chamber, we were able to define six major drivers to address three key issues: (1) reduce wet clean time, (2) eliminate system complexity, and (3) achieve technical excellence. Key components of the MxP+ that allow us to address them include a quartz gas distribution plate which prevents the aluminum particle formation, and the electrostatic chuck which eliminates the mechanical clamp system while reducing the particle contamination and wafer edge exclusion. The unique chamber liners of the MxP+ not only shield chamber walls, but also provided a wide process wi...