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G. L. Miller

Bio: G. L. Miller is an academic researcher from Alcatel-Lucent. The author has contributed to research in topics: Ion plating & Deposition (phase transition). The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors have made a systematic study of the microstructure and stress of W thin films using a variety of characterization techniques, and they have shown the feasibility of depositing low-stress (<10 MPa) W films by in-situ stress monitoring and control of sputtering pressure.
Abstract: Sputter-deposited tungsten thin films exhibit high intrinsic stress. This stress can result in both in-plane and out-of-plane distortion when the films are deposited on thin membrane structures such as x-ray masks. To minimize these distortions, intrinsic stresses in these absorber films have to be low and reproducible. Several groups have recently reported that by precisely controlling the sputter deposition conditions, W films with low stresses can be produced. However, the reproducibility is limited. We have built a novel acoustic resonance system, in which one electrode, mounted behind the mask membrane, monitors its position and simultaneously provides an electrostatic drive to keep it vibrating at its resonant frequency. For typical membranes and deposition conditions, vibrational modes in the 1–10 kHz range are observed. During tungsten deposition, sputtering pressure is varied in response to changes in the membrane resonant frequency, so that the film stress is minimized. We have made a systematic study of the microstructure and stress of W thin films using a variety of characterization techniques. We have shown the feasibility of depositing low-stress (<10 MPa) W films by in-situ stress monitoring and control of sputtering pressure. By using a proper combination of substrate heating and sputter power density (thermal engineering), the reproducibility of in-situ stress control is greatly improved. The present experimental results of in-situ stress control during W sputter deposition are very promising for the successful utilization of low stress (<10 MPa) W films as absorbers for x-ray masks.

4 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the requirements for deep x-ray lithography (DXRL) masks are reviewed and a recently developed cost effective mask fabrication process is described, including a summary of tabulated properties for materials used in the fabrication of DXRL masks.
Abstract: The requirements for deep x-ray lithography (DXRL) masks are reviewed and a recently developed cost effective mask fabrication process is described. The review includes a summary of tabulated properties for materials used in the fabrication of DXRL masks. X-ray transparency and mask contrast are calculated for material combinations using simulations of exposure at the Advanced Light Source (ALS) at Berkeley, and compared to the requirements for standard x-ray lithography (XRL) mask technology. Guided by the requirements, a cost-effective fabrication process for manufacturing high contrast masks for DXRL has been developed. Thick absorber patterns () on a thin silicon wafer (m) were made using contact printing in thick positive (Hoechst 4620) and negative (OCG 7020) photoresist and subsequent gold electrodeposition. Gold was deposited using a commercially available gold sulphite bath with low current density and good agitation. The resultant gold films were fine-grained and stress-free. Replication of such masks into thick acrylic sheets was performed at the ALS.

23 citations

Journal ArticleDOI
TL;DR: In this article, a new system that measures stress in film deposited on Si wafers has been developed to produce highly accurate X-ray masks, which consists of very rigid air sliders, an electrostatic sensor, and a soft-handling wafer chuck.
Abstract: A new system that measures stress in film deposited on Si wafers has been developed to produce highly accurate X-ray masks. The system consists of very rigid air sliders, an electrostatic sensor, and a soft-handling wafer chuck. With the system, wafer warp is precisely measured before and after film deposition, and the stress distribution is calculated from those measurements. Wafer warps can be measured with a repeatability of a few nanometers by this system. The stress distribution of absorber film on 2-mm-thick Si wafers can be determined with an accuracy of ±5 MPa. The stress distribution agrees well with the pattern position shifts in the membrane.

5 citations

Proceedings ArticleDOI
R. G. Tarascon1
03 Jul 1995
TL;DR: In this paper, the authors evaluate the performance of enhanced optics, proximity x-ray and projection electron-beam which extend the state of lithography below 0.25 micrometers and show that the success of any of these new techniques is directly connected to the ability to manufacture the corresponding mask.
Abstract: As the design rules to make integrated circuits with features less than 0.25 micrometers are emerging, it appears that conventional deep UV photolithography will not be able to support these new generation IC technologies. There are however other possibilities such as enhanced optics, proximity x-ray and projection electron-beam which extend the state of lithography below 0.25 micrometers . AT&T is in a unique position to evaluate these new technologies since we have active programs in each of these areas. It is clear that the success of any of these new techniques is directly connected to the ability to manufacture the corresponding mask.

4 citations

31 Jan 1991
TL;DR: Tungsten chemical vapor deposition (W-CVD) using WF6 and H2 as reactants was applied to forming absorbers of X-ray masks for synchrotron radiation (SR) lithography as discussed by the authors.
Abstract: Tungsten chemical vapor deposition (W-CVD) using WF6 and H2 as reactants was applied to forming absorbers of X-ray masks for synchrotron radiation (SR) lithography. For this purpose, the properties of deposited W (CVD-W), such as stress, density and thermal stability, were examined. The stress can be minimized reproducibly to less than 1×108 dyn/cm2 by controlling the flow rate of WF6 at various substrate temperatures. This W film was thermally stable up to 200°C, and the density was 18.5 g/cm3. From these results, CVD-W was found to be suitable as an absorber material. For the formation of absorber patterns, filling SiO2 grooves with stress-reduced CVD-W was examined. The 0.2-µm-wide grooves were filled with CVD-W and absorber patterns were formed by etch-back. The X-ray mask was successfully fabricated by this developed process.