A new dual bottom antireflectant consisting of an organic antireflectant and a SixOyNz:H (SiON) layer has been designed for metal layers to cover both 45nm and 32nm node logic devices. Simulations have been used to optimize the optical constants of the organic antireflectant. The new antireflectant system has been evaluated on a 1.2NA tool for metal layers. The same organic antireflectant has been successfully applied to via layers at a different thickness. The overall patterning performance including profiles, line width roughness (LWR), overlap depth of focus margin (ODOF) and critical dimension (CD) uniformity before and after etch has been evaluated. The new antireflectant system meets all the patterning requirements for a manufacturable process. An immersion tool at 1.2NA was used to perform lithography tests. Simulation was performed by using ProlithTM software.
This study combines simulation and experiment to compare the impact that changing BARC thickness
around some nominal value has on the resist profile, on an underlying reflective surface. Process window
and profile effects are an important part of understanding how a BARC interacts with the resist's
parameters to affect the latitude in the light of imperfect reflection control. Reflectivity simulations are
made using MATLAB(r); and ProlithTM that show the effect of choosing refractive index and thickness in a
multi-layer bottom anti-reflecting coating (BARC). Trends are identified for the better operating values for
the index as well as specific values that meet the criterion for organic BARC in a front end application on a
reflective substrate. Experimental profiles are compared to simulation using a calibrated resist model for
nominal, better and ideal BARC stacks. Reflectivity, as a function of angle in resist, is convolved with the
diffraction intensity distribution. This reflection, determined by a pitch's diffraction angle, identifies what
can become problematic in setting up a process. Depolarization causes are discussed and while their impact
affects image formation, there is little difference in reflection.
Bandwidth demand is still growing and it is becoming more difficult for copper based interconnect technologies to meet system requirements. Considerable progress is being made in the development of optical interconnect technology. Recent publications have shown improved integration of turning mirrors and connectors for board level applications. This paper presents recent work on a siloxane-based waveguide material that is optimized for 850nm board level optical interconnect applications. The material under development is a negative acting photoimageable material that can be processed with conventional Printed Wire Board (PWB) or CMOS processing techniques and chemistries. Meter long waveguides have been fabricated on both silicon and FR4 substrates with optical loss performance of 0.027dB/cm and 0.067dB/cm respectively. Data illustrating the effect of bend radii and splitter performance is reported. Lastly, the ability of the siloxane material to withstand PWB fabrication and assembly processes such as lamination, metallization and reliability is demonstrated.
The drive to faster data transmission speeds, more integration, smaller form factors and higher signal integrity all favor the eventual adoption of optical transmission schemes in data buses. This contribution will discuss emerging technologies from Shipley Company, LLC to address the needs of optoelectronic signal transmission. In particular, the discussion will focus on materials and processes that are in development to function within existing printed circuit board (PCB) & microelectronic manufacturing schemes. One topic that is described in detail involves photo-patternable, polymer interconnect technologies. Another topic describes progress in Shipley’s ability to integrate these interconnects into prototypical PCB processes. Progress in connecting the planar waveguides to connectorization schemes will be also be described. Other topics include lithographic and patterning metrics, optical characteristics of interconnects, morphological features of patterned waveguides, integration and coupling considerations, thermal and mechanical properties of the system and general assembly processes..
There are a number of organic, inorganic, and hybrid inorganic waveguide materials that are currently being used for a wide variety of optical interconnect applications. Depending upon the approach, waveguide formation is performed using a combination of lithographic and/or reactive ion etch (RIE) techniques. Often the processes involved with waveguide formation require unique processing conditions, hazardous process chemicals, and specialized pieces of capital equipment. In addition, many of the materials have been optimized for silicon substrates but are not compatible with printed wire board (PWB) substrates and processes. We have developed compositions and processes suitable for the creation of optical, planar waveguides on both silicon and PWB substrates. Based on silicate technology, these compositions use lithographic techniques to define waveguides, including aqueous, alkaline development. The resulting planar waveguides take advantage of the glass-like nature of silicate chemistry wedded with the simplicity of standard lithographic processes. Attenuation at typical wavelengths has been found to compete well with the non-silicate-based technologies available today. Single-mode (SM) and multi-mode (MM) waveguides with losses ranging from 0.6 dB/cm @ 1550nm, 0.2 dB/cm @1320nm, and <0.1 @ 850nm are feasible. Composition, process, and physical properties such as optical, thermal and mechanical properties will be discussed.
Recently several authors have specifically noted the advantages of using negative tone resists for patterning narrow trenches. The growing interest stems from several factors. Firstly aerial image models indicate that negative tone systems should have improved process windows for patterning narrow trenches, relative to their positive tone counterparts. Secondly, negative tone resists are thought to be advantageous for minimizing variations of CD through pitch for trench layers thus reducing the optical proximity effect for certain exposure conditions. Finally, negative tone systems arguably circumvent the issue of resist poisoning from low k dielectric materials. The combination of these arguments has warranted our effort in the development of negative tone 193 nm resist systems, and this submission will present recent advances in this area. In particular the presentation will focus on prototypical negative tone formulations for use in patterning trenches with bright field imaging. We will present our results on a variety of performance attributes such as dissolution behavior, LER control, etch performance, resolution and process windows for these systems and we will provide a materials basis for using negative tone systems for patterning trenches for back end layers.
Surface roughness of 193 nm resists after a dry etch process is one of the critical issues in the implementation of 193 nm lithography to sub- 100 nm technology nodes. Compared to commercial 248 nm resists, 193 nm photoresists exhibit significant roughness especially under the etch conditions for dielectrics, such as silicon dioxide and silicon nitride. While AFM analysis of DUV resists exhibit the mean roughness (Ra) of ~1 nm after blanket oxide etch, Ra’s of 193 nm resists were found to be in the range of 4 to 7 nm depending on the chemical structure of the resist backbone. In an effort to develop 193 nm resists with improved post-etch roughness (PER), we carried out exhaustive screening of the available 193 nm resist platforms using bulk oxide etch followed by AFM analysis of the resist surface. Benchmarking results indicated that cyclic olefin copolymers, prepared by vinyl addition copolymerization of norbornene derivatives, exhibit significantly better PER than (meth)acrylic copolymers, cyclic olefin/maleic anhydride (COMA) copolymers, or COMA/(meth)acrylic copolymers (COMA hybrid). In this paper, are addressed various factors that influence PER of 193 nm resists and presented solutions to overcome etch inferiority with 193 nm resists for the real device fabrication.
ArF lithography is the current ramp-up technology for next generation devices. However, some manufacturing issues still remain when considering the resist design for the most advanced processes. Several polymer platforms have been proposed, among them, Methacrylate, CycloOlefin-alt Maleic Anhydride, and even pure Cyclo-Olefin. More recently, Vinyl-Ether Maleic Anhydride (VEMA) polymers have demonstrated potential in terms of both lithographic properties and etch capabilities. In this paper, the evaluation of some advanced samples of VEMA resists for 120nm and sub-120 nm gate applications will be discussed. The various criteria investigated for this study were; focus and exposure latitude for 120 and 100 nm lines (1/1.5 L/S to isolated lines), Iso-Dense bias, Line End Shortening (LES), Line Edge Roughness (LER), masking linearity, BARC compatibility, sensitivity to PEB temperature and electron beam, and finally etch resistance. Additionally some process optimizations were tested in order to minimize Iso-Dense Bias and the LER of the resists (See figure 1). In fact, this latter parameter has been a major focus of this work in improving the VEMA resist chemistry since its introduction and preparing it for device manufacture. The results obtained when varying parameters such as resist formulation, development conditions will be reported and so will demonstrate the current maturity of the most advanced VEMA samples.
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