Characteristics of long afterglow phosphorescent calcium aluminate crystals for fluorescence thermometer application

Layers are patterned with a lithography method during the fabrication of integrated circuits. A mask, which may be reflective or transmissive, for carrying out the method. The photosensitive layers are exposed to radiation that is emitted by a radiation source. The radiation lies in the extreme ultraviolet region and is guided via the mask onto the photosensitive layers.

Lithography method and lithography mask

Growth and characteristics of a new long afterglow phosphorescent yttrium tantalate crystal

Inorganic SiON BARC has been used widely in I-line lithography and 248nm DUV lithography because of its good photo performance and tunable reflective index (n) and extinction coefficient (k) on specific substrates. Conventional single layer SiON BARC on poly, WSix or Al (TiN) has successfully enhanced CD control. However, when applying single layer SiON BARC on top of oxide hard mask, tight thickness control of hard mask becomes a major issue in order to maintain the substrate reflectivity for good photo performance. Dual layer SiON BARC presented in this paper resolves the issue with wide range of hard mask thickness control. Unlike conventional organic BARC where the absorption is the primary mechanisms and the conventional single layer inorganic BARC where phase shift cancellation is dominant, the dual layer BARC uses both phase shift cancellation and light absorption mechanism. The design of dual layer BARC is that top layer serves as phase shift cancellation layer and bottom layer serves as light absorption layer with high k value. Therefore, with fixed bottom absorption layer, top layer n and k and thickness can be fine tuned to get the best photo performances. The advantages of dual layer SiON BARC are that there is no need for the tight BARC thickness control as in the case of single layer SiON BARC as well as for hard mask thickness control. Since the light is all absorbed by the bottom BARC layer, the periodical phenomena of light passing through transparent hard mask film does not exist. Detail information of setting up dual layer SiON BARC by both simulation and experiment are described here. The comparison between dual layer BARC and single layer BARC shows that smaller swing ratio and tighter CD control can be obtained in the case of dual layer BARC. Similarly, the comparison between dual layer SiON BARC and organic BARC shows that smaller iso-dense bias and better resist profile can be obtained with dual layer SiON BARC.

Dual-layer inorganic SiON bottom ARC for 0.25-μm DUV hard mask applications

We present an approach for periodical structuring of large-area photoresist gratings with short periods based on a deep-ultraviolet (DUV) lithography process. Our procedure of inscribing gratings on planar surfaces using a scanning phase-mask interferometer and including a technique for suppressing the disturbing influence of the zeroth-order diffraction is demonstrated and compared to well-established methods. Applying this approach, large-area, centimeter-scale chirped photoresist gratings with a central period of 225 nm, a chirp rate of 0.5 nm/cm and a duty cycle of 50% have been fabricated on planar silicon chips.

Scanning Phase-Mask DUV Inscription of Short-Period Large-Area Photoresist Gratings

BARC technology, originally developed for gate level has now to be applied to interconnection one's. Requirements for dielectric interconnection levels are different from gate level. In the case of gate level ARC has to minimize reflectivity at resist/substrate interface due to notching and resist swing curve effects. Whereas ARC for interconnections has to minimize reflectivity variation at resist/substrate interface due to swing curve effect in the dielectric layer. For interconnection, ARC must be as absorbent as possible at stepper exposure wavelength, and two ways are foreseen: ARC layer with high k value at 248 nm, and ARC layer with high thickness. For a reflectivity variation minimum criteria, we can find a couple values (k, minimum thickness). Experiments give us for a reflectivity variation below 5% the following couples: (k equals 0.7, 1200 angstroms thickness) and (k equals 1.1, 850 angstroms). In this paper we describe different applications of SiOxNy for interconnection levels: via, contact and damascene line level. Improvements depending of the SiOxNy thickness are seen in CD dispersion. To conclude SiOxNy ARC can be used for interconnection levels, and its performance depends on ARC couple values (k, thickness).

Inorganic bottom ARC SiOxNy for interconnection levels on 0.18-μm technology

Manufacturing the next generation of devices will demand lithographic capability in the sub-0.18 µm range. The phase shift mask (PSM) is a key emerging technology which is thought to extend 248 nm optical lithography. Using the Levenson PSM technique allows us to improve resolution by as much as 50% at gate level. This paper describes the lithographic performances of the Shipley UV5 photoresist on SiOxNy bottom antireflective coating (BARC), using alternating PSM and an ASM/90 Deep UV stepper. Critical dimension (CD) measurement was done on an OPAL 7830i metrology scanning electron microscope (SEM). Results on sub-0.18 µm design rules are presented as follows. –The first part concerns experimental conditions: masks, process conditions, anti-reflective substrates, etching and metrology are discussed. –The second part concerns lithographic performances: process linearity from 0.12 µm to 0.18 µm, 0.12 µm isolated line process latitudes of 7% energy latitude for 0.8 µm depth of focus (DOF) have been exhibited. Finally we try to evaluate the proximity effect and the ultimate resolution of this technology.

0.12 µm Optical Lithography Performances Using an Alternating Deep UV Phase Shift Mask

The phase shift mask (PSM) is a key emerging technology thought to be extending 248 nm lithography. In this paper, we describe the lithographic performances of Shipley UV5 photoresist on SiOxNy Bottom Anti Reflective coating (BARC), using alternating PSM and ASM/90 Deep-UV stepper. Results on 0.18 micrometer design rules are presented: lithographic performances, comparison between PSM and binary mask, sub 0.18 micrometer performances ({1}) and the ultimate resolution of this technology are reported. To conclude we demonstrated the 0.18 micrometer lithography feasibility with alternating mask and KrF stepper, and showed that all the necessary tools are today available to achieve such goals.

0.18-μm optical lithography performances using an alternating DUV phase-shift mask

The goal of this paper is to understand the optical phenomena at dielectric levels. The purpose is also to quantify the impact of dielectric and resist thickness variations on the CD range with and without Bottom Anti Reflective COating (BARC). First we will show how all dielectric levels can be reduced to the stack metal/oxide/BARC/resist, and what are the contributions to resists and dielectric thickness range for each levels. Then a simple model will be developed to understand CD variation in this tack: by extending the Perot/Fabry model to the dielectric levels, developed by Brunner for the gate level, we can obtain a simple relation between the CD variation and all parameters. Experimentally CD variation for Damascene line level on 0.18micrometers technology has been measured depending on oxide thickness and resist thickness and can confirm this model. UV5 resist, AR2 BARC from Shipley and Top ARC from JSR have been used for these experiments. The main conclusions are: (1) Depending on your dielectric deposition and CMP processes, if resist thickness is controlled, a standard BARC process used for the gate is adapted to remove oxide thickness variation influence providing the optimized resist thickness is used. (2) If both resist thickness and dielectric thickness are uncontrolled, a more absorbent BARC is required.

New trends in Brunner's relation: dielectric levels

The goal of this paper is to understand the optical phenomena at dielectric levels (contact, local interconnect, via and damascene line levels). The purpose is also to quantify the impact of dielectric and resist thickness variations on the CD range with and without Bottom Anti Reflective Coating (BARC). First we will show how all dielectric levels can be reduced to the stack metal/oxide/BARC/resist, and what are the contributions to resist and dielectric thickness range for each levels. Then a simple model will be developed to understand CD variation in this stack: by extending the Perot-Fabry model to the dielectric levels, developed by Brunner for the gate level, we can obtain a simple relation between the CD variation and all parameters (metal, oxide thickness, resist thickness, BARC absorbency). Experimentally CD variations for damascene line level on 0.18 micrometers technology has been measured depending on oxide thickness and resist thickness and can confirm this model. UV5 resist, AR2 BARC from Shipley and Top ARC from JSR have been used for these experiments.

Yves Quere

Papers

Inorganic bottom ARC SiOxNy for interconnection levels on 0.18-μm technology

0.12 µm Optical Lithography Performances Using an Alternating Deep UV Phase Shift Mask

0.18-μm optical lithography performances using an alternating DUV phase-shift mask

New trends in Brunner's relation: dielectric levels

Lithographic CD variation in contact, via, local interconnect, and damascene levels