William M. Goodwin

Accelerated testing technique for evaluating performance of chemical air filters for DUV photolithographic equipment

In this paper, the authors discuss the requirements for chemical air filtration system used in conjunction with modern DUV photolithography equipment. Among the topics addressed are the scope of pollutants, their respective internal and external sources, and an overview of different types of filtration technologies currently in use. Key filtration parameters, including removal efficiency, service life, and spill protection capacity, are discussed and supported by actual data, reflection the total molecular base concentration in operational IC manufacturing facilities. The authors also describe a time-accelerated testing procedure for comparing and evaluating different filtration technologies and designs, and demonstrate how this three-day test procedure can reliably predict an effective filter service life up to ten years.

Real-time amine monitoring and its correlation to critical dimension control of chemically amplified resists for sub-0.25-μm geometries

One such issue is the quantitative control of critical dimension (CD) and how to calibrate fab contamination levels to linewidth control. Since most fabs build several generations of devices, contamination levels for older generations may not be suitable for new generations. Therefore, studies to control CD for each generation are required to determine the effectiveness of filtration schemes. In this paper the authors have investigated CD control for imaging dimensions from 0.25 micrometers to 0.15 micrometers . We have also correlated this data back to chemical monitoring levels to determine CD vs. PED stability for these geometrys to determine the contamination level tolerance. Additionally, the authors have generated process windows to determine the effect such delays have on process windows.

More on practical solutions to eliminate reticle haze and extend reticle life in the production environment: specially designed RSPs, internal POD purifiers, and XCDA purged reticle stockers

Use of specially designed reticle SMIF pods (RSPs) - with unique purge flow, internal dual-capture mechanism purifiers and an ultra-low humidity CDA purging system- have provided a practical solution to eliminate reticle haze for the useful life of the reticle in production environments. Prior publications, Kishkovich et al., described newly understood mechanisms of reticle haze formation based on chemical modification of quartz and chrome surfaces and have proposed solutions based on continual purge of the reticle environment with ultra-low humidity purified air [1]. In further publications they reported successful application of this solution in the field on single reticle-pod purge systems. [2] In this paper we provide guidance and advice for high volume manufacturing haze control practitioners, describing some challenges and solutions implemented on reticle stocker equipment, including considerations for materials of construction, purge flow levels and regulation, in-pod moisture/chemical purifiers, and on-tool flow measurement techniques.