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Ta (N)/Ta bi-layer is a commonly used barrier in damascene copper interconnects for 90nm and 65nm technology nodes. A new barrier integration scheme so-called punch-through is currently used for 65nm node. The main feature of the new deposition scheme is to introduce an etch-back step between the Ta (N) layer deposition and the Ta layer deposition. This intermediate etch step cleans up the bottom of via and also partially etch the underlying copper line with a depth of few nanometers. This step changes dramatically the bottom of via shape leading to via anchoring into the underlying copper line. In this paper we compare punch-through versus no punch-through approach. We show that the punch-through leads to a lower via resistance and to a tighter via resistance distribution, while keeping line resistance similar. We show that via anchoring into the underlying copper line coupled with a better tantalum step coverage dramatically reduces stress migration effect and also improves electro-migration performances at 65nm technology node.

In the development of damascene copper interconnects for the 90 and 65nm technology nodes, several diffusion barriers were considered. Among barrier films a TaN/Ta bilayer is preferred because of its excellent adhesion to dielectrics and good barrier properties. In a typical process, the bilayer deposition includes four steps: TaN deposition, target reconditioning, Ta deposition, and resputtering. In this study, we define critical process parameters and characterize thin barriers for improved effective line and via resistance. Results on blanket wafers indicate that the TaN deposition time directly influences barrier thickness while the Ta deposition time mainly influences sheet resistance and the full bilayer stack. Additionally, decreasing DC power and deposition time does not induce any change on Ta; however, TaN films are influenced by DC power and deposition as shown by XRD. Critical parameters influencing the 90nm technology performance include deposition time of TaN and Ta. Gas flows or bias resputtering show no significant impact on sheet resistance or film properties within the scope of this study. Experiments on 65nm node highlight the role played by the tantalum deposition on the via chain yield. These results presented in this paper clarify the role of individual process steps during the barrier deposition.

The 4 GeV/c high resolution spectrometers of the CEBAF experimental Hall A require two mirror imaged superconducting quadrupole magnets of cosine 2/spl theta/ coil configuration. These magnets are presently under construction at Saclay under a SURA/CEBAF contract. The basic parameters are: 300 mm clear bore, 918 mm magnetic length, quadrupole field gradient 8.5 T/m with a 1/spl times/10/sup -3/ uniformity. The paper describes the 3D method used to adjust the coil geometry and gives mechanical, cryogenic and electrical parameters. It includes cable concept and manufacture procedures. >

The authors describe the test facility and the cryogenic and magnetic measurements performed on the twin aperture prototype (TAP) dipole for the CERN Large Hadron Collider (LHC). The magnet, designed by CERN and built by European industries, was tested in a facility built at CE Saclay. The focus is on the cryogenic system, which enables prototype magnets to be tested in superfluid helium; on the data acquisition systems, including a system for magnetic measurements; and on the results which were obtained during the tests. >

An enhanced trench first hard mask (TFHM) backend integration architecture has been developed to facilitate straightforward ultra low-k (ULK) material insertion and to enable rapid yield learning at the 65nm technology node. Parametric, yield, reliability, and RC performance data are presented for the fully-integrated, improved TFHM 300mm ULK backend

A 45nm node BEOL integration scheme is presented with 140nm metal pitch at local and intermediate levels and 70nm via size. The dual damascene (DD) process is performed in a full porous low-k (k=2.5) at line and via level in order to meet RC performance requirements. Parametrical results show functional via chains and good line resistance and serpentine continuity at 45nm node dimensions. Copper resistivity and electromigration performances were investigated for line widths below 50 nm upon using ALD and PVD barriers

Mechanical reliability is widely recognized as the primary obstacle to productionization of porous low-k materials. The combination of weak bulk and interfacial properties with increasingly complex geometries poses a considerable challenge at the 65-nm node. The final solution must be sufficiently robust so as to ensure compatibility with multiple substrate types, interconnect configurations and packages. In this work, material engineering, modeling, design rule tailoring, and assembly optimization are employed to achieve required assembly reliability for both wirebond and flip-chip packages, for both bulk and SOI substrates.

This work highlights the realization and 0.248/spl mu/m/sup 2/ to 0.334/spl mu/m/sup 2/ SRAM bit-cells with conventional bulk technology based on 19/spl Aring/ CET SiON gate oxide, poly-silicon gate electrode, and mobility enhancement techniques for both nMOS and pMOS. High density critical lithography levels have been exposed with e-beam direct writing thus contributing to the overall cost-effectiveness of the technology.

Given the much discussed challenges of interconnect scaling at the 65-nm node, the choice of process architecture is a key determinant of performance and extendibility. An alternate trench-first with hardmask integration is described in this work, including subsequent benefits. BEOL design rules are detailed for the 65-nm architecture, supporting both "low-k" and "ultra-low-k" backends, satisfying RC scaling requirements. Electrical parametric performance and yield are presented for a fully-integrated 300mm backend utilizing 65-nm design rules demonstrating the viability of this architecture for the 65-nm node and beyond.

Within the framework of the LHC (Large Hadron Collider) R&D program, CERN and CEA/Saclay have established a collaboration to carry out the design, building and testing of a superconducting LHC prototype quadrupole at the Saclay laboratory. The cold mass of this quadrupole is presently under construction at Saclay. The quadrupole design features a twin aperture configuration, a gradient of 250 T/m, a length of 3 m, and a free coil aperture of 56 mm. European industries participate in this project by delivering components and fabricating the tooling according to specifications prepared by Saclay. The authors present details of the magnet design and construction. Coil winding will start in summer 1991 and the first prototype should be assembled and ready for testing by mid 1992. >

A 5 T superconducting wiggler has been installed in the DCI storage ring and operated successfully without any noticeable disturbance of the 100 mA positron beam at 1.72 GeV. This device is primarily intended to increase the photon flux at short X-ray wavelengths by shifting the characteristic wavelength. However, because it is a five-pole magnet it delivers an X-ray beam far more intense than the one from the bending magnets, even at wavelengths longer than 1 A. The magnet was designed and constructed at the DPhPE of CEA Saclay to specifications from LURE.

A large superconducting solenoid (5-m bore, 7-m length) has been designed and constructed at the CEN/Saclay for the ALEPH detector, to be installed on the LEP collider at CERN. Special features of this solenoid are described such as the Al-stabilized superconducting cable, bobbinless internal winding, vacuum impregnation, indirect cooling, thermosyphon refrigeration mode, cryostat assembly. Preliminary tests without the iron carried out successfully in April 1987, and a complete test with the iron calorimeter at CERN in September 1987 are briefly reviewed. >

A description is given of a superconducting wiggler built and tested at Saclay for the Laboratoire pour l'Utilisation du Rayonnement Electromagnetique (LURE) at Orsay, France. The wiggler is being used as light source on the 1.72-GeV positron beam of the DCI storage ring at Orsay to increase the photon flux at short X-ray wavelengths. The magnet has five half-periods of field with a central amplitude of nearly 5 T, two middles with -3.6 T, and two ends with 2 T. The period length is 260 mm, the magnet gap is 67 mm, and the room-temperature beam chamber gap is 30 mm. The field is produced by ten superconducting coils embedded in a soft iron yoke which contains the magnetic forces. A correction current is applied to the end coils to ensure a zero integral field in the whole range of field. The results of three magnet training tests are briefly discussed. >