Simone Alba

Study Of Plasma Charging And Photoresist Coating Effects Using UV-erased FLASH Cell As Charging Sensor

This paper describes a novel methodology based on UV-erased FLASH memory cells, that does not require high Voltage programiming before plasma exposure. The methodology was used to evaluate a production TCPTM metal etcher. Bare wafers and wafers coated with photoresist were compared. Charging effects due to the patterning process have been identified and eliminated by proper process change.

Effect of pulsed plasma, pressure, and RF bias on electron shading damage

The electron shading damage mechanism as proposed by Hashimoto has been widely accepted as the major charge damage mechanism for the current device generation. Vahedi et al derived an analytic model that clarifies the contribution of plasma and device parameters in topography induced charging. The effects predicted by the analytic model have been verified by our previous work. This continuation of the work examines the role of plasma parameters on V/sub th/-shifts in transistors fabricated with a Flash memory process where metal 1 was etched in a Lam TCP/sup TM/ 9600 PTX chamber. The roles of low pressure, RF bias, and pulsed plasmas in reducing damage were investigated using these antenna device wafers. Initial results appeared to contradict analytic mode predictions, but investigation of the topography changes during etch eliminated the contradictions and is leading to work on a refined analytic model taking dynamic effects into consideration.

Real time evaluation of an air leak into a dry etching equipment by means of optical emission spectroscopy: evaluation and results in high volume production regime

Chamber leak test is one of the most important tests that are performed on plasma reactors for etch, CVD, etc. Optical Emission Spectroscopy OES is a powerful non-invasive tool to perform real time plasma diagnostic and in theory could be use as an alternative method to evaluate the air leak into the plasma reactor. The idea is to detect and quantify small differences in the emission spectrum of the plasma when a presence of a quantity of air is higher than the tolerated threshold. This would give the possibility to test the level of the leak chamber any time automatically during production or between wafers and hence to increase the frequency of testing. In this presentation we describe not only the method itself with the instrument set up and the test configuration adopted but also the experience acquired in high volume production regime and the numerous advantages obtained in comparison with the conventional leak rate test.

Metal etcher characterisation using flash memory cell as charging sensor

Abstract Fully processed Flash Memory cells have been used to characterise wafer charging damage in a Transformed Coupled Plasma production metal etcher. Wafers both bare and coated with photoresist were exposed to the plasma, and the actual process conditions were simulated by an Ar-reference discharge. Charging effects due to process parameter changes were evaluated, revealing a strong dependence on RF source configurations. The new methodology was demonstrated to be suitable for process control and production monitoring.

Metal etcher characterization using flash memory cells as charge sensors

In this work, flash memory cells in 0.5 /spl mu/m technology have been used as charge sensors to characterize a Transformer Coupled Plasma (TCP) metal etcher. The philosophy of the method is analogous to that of CHARM wafers.