Investigation of EUV haze defect: molecular behaviors of mask cleaning chemicals on EUV mask surfaces

Choi, Jinsung; Novak, Steve; Kandel, Yudhishthir; Denbeaux, Greg; Lee, Han-Shin; Ma, Anna; Goodwin, Frank

doi:10.1117/12.916499

Cited by 2 publications

(3 citation statements)

References 21 publications

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“…Figure 4 compares the measured conductivity values of NH 4 OH diluted in water to a mixture of Chemistry A in water for different concentrations. It is interesting to notice that Chemistry A gives similar conductivity values as NH 4 OH, but at much lower concentration (about 70x lower). This is because the dissociation rate of Chemistry A in H 2 O is much higher than that of NH 4 OH.…”

Section: Ionization (Conductivity Ph and Zeta Potential)mentioning

confidence: 87%

“…DI water used for the tests is de-gassed before it was supplied to the cleaning chemical distribution system. Chemicals (NH 4 …”

Section: Process Parametersmentioning

confidence: 99%

“…This interaction between the negative species formed on the surface and the positive NH 4 + ions result into the material etching, which results into CD, phase and transmission change on the PSM masks. Some of these ions also diffuse into the bulk of the surface and later contribute to haze (progressive defects) occurrences during mask exposure in the lithography scanner [4]. [5,6].…”

Section: Introductionmentioning

confidence: 99%

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Effect of cleaning chemistry on MegaSonic damage

Singh¹,

Dietze²,

Dress

2013

SPIE Proceedings

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Acoustic energy applied through the cleaning media results into two kinds of cavitation effects; namely stable and transient cavitation. A uniformly pulsating bubble transforms into stable cavitation behavior whereas a bubble implosion implies transient cavitation. Pattern damage of sensitive features on advanced masks as well as Ru pitting on EUVL reticles is mostly the result of transient cavitation. Stable cavitation on the other hand produces a very narrowly controlled energy distribution which allows cleaning without damage. Stable cavitation can be achieved by suitably tailoring physical, chemical and thermodynamic properties of the liquid and gas media. In this paper we investigate a new cleaning chemistry that has favorable physical and thermodynamic properties to produce stable MegaSonic cavitation. The cavitation created in this chemistry is characterized by measuring acoustic energy as well as by pattern damage and particle removal efficiency on mask level. The chemical properties (pH & zeta potential) of this chemistry are compared with conventional cleaning chemistries. Its effects on CD shift as well as phase and transmission loss are also studied.

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Section: Ionization (Conductivity Ph and Zeta Potential)mentioning

confidence: 87%

“…DI water used for the tests is de-gassed before it was supplied to the cleaning chemical distribution system. Chemicals (NH 4 …”

Section: Process Parametersmentioning

confidence: 99%