EUV pellicle development for mask defect control

Shroff, Yashesh; Goldstein, Michael; Rice, Bryan J.; Lee, Sang H.; Ravi, K. V.; Tanzil, Daniel

doi:10.1117/12.656551

Cited by 32 publications

(15 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However more recent publications have revealed the feasibility when using a mesh in combination with an inorganic membrane (see for example Ref. 10). …”

Section: Projection and Illuminator Optics Quality And Lifetimementioning

confidence: 98%

Assessment of EUV reticle blank availability enabling the use of EUV tools today and in the future

Jonckheere

Lorusso

Goethals

et al. 2007

23rd European Mask and Lithography Conference

View full text Add to dashboard Cite

With first full-field exposure tools for extreme ultraviolet lithography (EUVL) materializing, the present paper intends to review the status of the EUV mask infrastructure to assure timely availability of reticles, first for the alpha demo tool (ADT), but also in preparation for future use of EUV lithography in production. First, the major requirements such as low thermal expansion substrates, multilayer reflectivity control, flatness requirements and absorber related requirements are reviewed and motivated. In a second part the status of the infrastructure is reviewed, and it is shown that both for mask blank suppliers and mask shops full-field EUV reticles bring new challenges. Because the mask blank infrastructure is critical to the success of EUV lithography, IMEC has addressed blanks vendors (together with ASML) and mask shops, to get first feedback on the challenges recognized for production tool masks, exploring key parameters that impact overlay and imaging. IMEC has prepared to obtain reticles with an identical layout from multiple mask shops. The present paper gives a snapshot of the available EUV mask infrastructure, with a focus on blank related aspects, in an anonymous way. It is a report of work in progress. Figure 1: Photograph of the ADT installed in the IMEC cleanroom. The tool is interfaced with a TEL ACT12 track, as shown in front of the ADT.

show abstract

“…However more recent publications have revealed the feasibility when using a mesh in combination with an inorganic membrane (see for example Ref. 10). …”

Section: Projection and Illuminator Optics Quality And Lifetimementioning

confidence: 98%

Assessment of EUV reticle blank availability enabling the use of EUV tools today and in the future

Jonckheere

Lorusso

Goethals

et al. 2007

23rd European Mask and Lithography Conference

View full text Add to dashboard Cite

show abstract

“…Kim et al 16 studied experimentally the stopping distances of speed-controlled 125 and 220 nm particles in a variety of air pressures from 25 to 100 mTorr, providing overall validation of the model of Asbach et al 15 The theoretical work of Asbach et al was extended to include particle diffusion effects, 17 and diffusional effects were compared with gravitational and thermophoretic forces for 10-500 nm particles, from 2 to 500 mTorr, presumably in air. 5 and 23-29) and also C. 30 Shroff et al proposed 23 supporting a Si film using a high optical transmission (>90%) Ni honeycomb mesh. Studies were also conducted by Asbach et al 18 and Yook et al 19,20 of the use of thermophoresis in mask protection in atmospheric air, with application to mask handling.…”

Section: Introductionmentioning

confidence: 99%

“…Although particle deposition probabilities were not calculated, the studies did suggest a steadily decreasing effectiveness of thermophoretic protection as the particles became more diffusive with decreasing size. Much work has been devoted to understanding the EUV transmission of such an assembly, 23,25 differential radiative heating of the supported film and mesh (which can lead to wrinkling), 26,28 and the effect of the Ni mesh on EUV image quality. Sogard has patented several mask protection approaches involving thermophoresis.…”

Section: Introductionmentioning

confidence: 99%

Protection of extreme ultraviolet lithography masks. I. Thermophoretic protection factors at low pressure for diffusing nanoscale particles

Klebanoff

Geller

Torczynski

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

View full text Add to dashboard Cite

Model calculations are presented for thermophoretic protection of an extreme ultraviolet (EUV) mask placed face down in an EUV mask inspection tool. The protection factors, defined as the ratio of challenge particles to deposited particles, are calculated for a variety of test conditions (temperature gradient, gas type, particle density, and particle position) for a reticle bathed in clean gas from a facing showerhead. Thermophoretic protection (in combination with gravity) provides robust protection for particle sizes greater than $20 nm. However, for particle sizes less than $20 nm, protection falters quickly and is severely degraded for highly diffusing 10 nm particles that are of concern for mask contamination. Estimates are made for the required level of particle protection in both EUV mask inspection and EUV projection lithography. When compared with these estimates for the required protection, it is clear that thermophoresis alone cannot successfully defend against particles smaller than $20 nm, and must be augmented or replaced by another approach. Initial calculations are presented that suggest a cross-cutting gas flow, in combination with thermophoresis and a face-down mask orientation, can successfully protect mask surfaces from particle deposition for particles with 10 nm diameter or greater, motivating more detailed calculations of flow-based mask protection in a companion paper Part II.

show abstract

“…The Pellicle surface can be contaminated, but since this surface is in out-of-focus with respect to wafers, particles are not printed on the wafer. The EUV light absorption is so high in any solid material that a pellicle is difficult to use, although there has been a study to try to develop a pellicle for EUVL [1]. Multiplayer reflective mirrors are used for optical components in EUVL, so that the light translates the pellicle twice, if it is placed in front of masks.…”

Section: Introductionmentioning

confidence: 99%

EUVL mask dual pods to be used for mask shipping and handling in exposure tools

et al. 2007

View full text Add to dashboard Cite

The concept of Extreme Ultra-Violet Lithography (EUVL) mask dual pods is proposed for use in both mask shipping and handling in exposure tools. The inner pod was specially designed to protect masks from particle contamination during shipping from mask houses to wafer factories. It can be installed in a load-lock chamber of exposure tools and evacuated while holding the mask inside. The inner pod upper cover is removed just before the mask is installed to a mask stage. Prototypes were manufactured and tested for shipping and for vacuum cycling. We counted particle adders through these actions with a detectable level of 54 nm and up. The adder count was close to zero, or we can say that the obtained result is within the noise level of our present evaluation environment. This indicates that the present concept is highly feasible for EUVL mask shipping and handling in exposure tools.

show abstract

EUV pellicle development for mask defect control

Cited by 32 publications

References 6 publications

Assessment of EUV reticle blank availability enabling the use of EUV tools today and in the future

Assessment of EUV reticle blank availability enabling the use of EUV tools today and in the future

Protection of extreme ultraviolet lithography masks. I. Thermophoretic protection factors at low pressure for diffusing nanoscale particles

EUVL mask dual pods to be used for mask shipping and handling in exposure tools

Contact Info

Product

Resources

About