Nelson Felix

Nelson Felix
IBM

About

101
Publications
27,439
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1,680
Citations
Citations since 2017
35 Research Items
961 Citations
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2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200

Publications

Publications (101)
Article
Background: The mathematical equations that explain overlay error of multiple-exposure patterning schemes have not been fully described in the literature and some commonly accepted methods lead to inaccurate estimated and/or measured overlay error. Aims: Develop the proper mathematical framework, using a first principles statistical approach, so th...
Article
The key challenge for enablement of a second node of single-expose EUV patterning is understanding and mitigating the patterning-related defects that narrow the process window. Typical in-line inspection techniques, such as broadband plasma and e-beam systems, find it difficult to detect the main yield-detracting defects postdevelop, and thus under...
Article
We report a sub-30-nm pitch self-aligned double patterning (SADP) integration scheme with EUV lithography coupled with self-aligned block technology targeting the back end of line metal line patterning applications for logic nodes beyond 5 nm. The integration demonstration is a validation of the scalability of a previously reported flow, which used...
Article
Full-text available
Extreme ultraviolet (EUV) patterning offers an opportunity to explore hardmask materials and patterning approaches. Traditional patterning stacks for deep ultraviolet patterning have been based on optimizing multilayer schemes for reflectivity control and pattern transfer. At the EUV wavelength, the patterning challenges are dominated by stochastic...
Presentation
Continued scaling in semiconductor technology nodes has seen the rise of multi patterning for several critical layers‚ leading to higher costs‚ variability‚ and process complexity. EUV direct print patterning can alleviate and address some of these issues. The insertion of this technology was showcased in 20161 by the IBM Alliance for back end of t...
Article
The ability to rapidly detect both printable EUV mask adder defects as well as mask absorber defects across the entire mask image field is a key enabler for EUV lithography. Current optical wafer-based inspection techniques are only capable of detecting repeater defects on a Die-to-Die basis for chiplets within the image field. Larger server-type c...
Article
Initial readiness of extreme ultraviolet (EUV) patterning has been demonstrated at the 7-nm device node with the focus now shifting to driving the "effective" k1 factor and enabling the second generation of EUV patterning. In current EUV lithography, photoresist thicknesses <30 nm are required to meet resolution targets and mitigate pattern collaps...
Article
Full-text available
With the increasing prevalence of complex device integration schemes, trilayer patterning with a solvent strippable hardmask can have a variety of applications. Spin-on metal hardmasks have been the key enabler for selective removal through wet strip when active areas need to be protected from dry etch damage. As spin-on metal hardmasks require a d...
Conference Paper
Successful pattern transfer from the photoresist into the substrate depends on robust layers of lithographic films. Typically, an alternating sequence of inorganic (most often Si containing) and organic hardmask (HM) materials is used. Pattern transfer occurs then by using reactive ion etch (RIE) chemistry that is selective to one particular layer...
Article
We report a systematic study of the feasibility of using directed self-Assembly (DSA) in real product design for 7-nm fin field effect transistor (FinFET) technology. We illustrate a design technology co-optimization (DTCO) methodology and two test cases applying both line/space type and via/cut type DSA processes. We cover the parts of DSA process...
Conference Paper
Full-text available
We present a 7nm technology with the tightest contacted poly pitch (CPP) of 44/48nm and metallization pitch of 36nm ever reported in FinFET technology. To overcome optical lithography limits, Extreme Ultraviolet Lithography (EUV) has been introduced for multiple critical levels for the first time. Dual strained channels have been also implemented t...
Article
Traditional patterning stacks for deep ultraviolet patterning have been based on a trilayer scheme with an organic planarizing layer, silicon antireflective coating or organic bottom antireflective coating, and photoresist. At an extreme ultraviolet (EUV) wavelength, there is no longer a need for reflectivity control. This offers an opportunity to...
Conference Paper
Directed self-assembly (DSA) of block copolymers (BCPs) has become a promising patterning technique for 7nm node hole shrink process due to its material-controlled CD uniformity and process simplicity.[1] For such application, cylinder-forming BCP system has been extensively investigated compared to its counterpart, lamella-forming system, mainly b...
Conference Paper
In recent years major advancements have been made in the directed self-assembly (DSA) of block copolymers (BCP). DSA is now widely regarded as a leading complementary patterning technique for future node integrated circuit (IC) device manufacturing and is considered for the 7 nm node. One of the most straightforward approaches for implementation of...
Conference Paper
In this paper, we discuss the lithographic qualification of high transmission (High T) mask for Via and contact hole applications in 10nm node and beyond. First, the simulated MEEF and depth of focus (DoF) data are compared between the 6% and High T attnPSM masks with the transmission of High T mask blank varying from 12% to 20%. The 12% High T bla...
Conference Paper
Self-Aligned Quadruple Patterning (SAQP) is a promising technique extending the 193-nm lithography to manufacture structures that are 20nm half pitch or smaller. This process adopts multiple sidewall spacer image transfers to split a rather relaxed design into a quarter of its original pitch. Due to the number of multiple process steps required for...
Conference Paper
Gate-all-around (GAA) nanowire (NW) devices have long been acknowledged as the ultimate device from an electrostatic scaling point of view. The GAA architecture offers improved short channel effect (SCE) immunity compared to single and double gate planar, FinFET, and trigate structures. One attractive proposal for making GAA devices involves the us...
Conference Paper
The use of EUV photomasks in a semiconductor manufacturing environment requires their periodic inspection to ensure they are continually free of defects that could impact device yield. Defects typically occur from fall-on particles or from surface degradation such as “haze”. The proposed use of a polycrystalline-based EUV pellicle to prevent fall-o...
Conference Paper
Several 27nm-pitch directed self-assembly (DSA) processes targeting fin formation for FinFET device fabrication are studied in a 300mm pilot line environment, including chemoepitaxy for a conventional Fin arrays, graphoepitaxy for a customization approach and a hybrid approach for self-aligned Fin cut. The trade-off between each DSA flow is discuss...
Conference Paper
The left side and right side line edge roughnesses (LER) of a line are compared for different conditions, such as through pitch, through critical dimension (CD), from horizontal to vertical line direction, from litho to etch. The investigation shows that the left and right side LER from lithography process are the same, however, the metrology can c...
Conference Paper
The feature scaling and patterning control required for the 7nm node has introduced EUV as a candidate lithography technology for enablement. To be established as a front-up lithography solution for those requirements, all the associated aspects with yielding a technology are also in the process of being demonstrated, such as defectivity process wi...
Conference Paper
Having a well designed overlay metrology target is one of the ways to improve on-product overlay performance. The traditional screening method in which multiple targets types are added to successive reticle tape outs and then evaluated by trial-and-error may not suffice for the 7nm node and beyond. For instance, although segmentation of image-based...
Article
Successful implementation of directed self-assembly in high volume manufacturing is contingent upon the ability to control the new DSA-specific local defects such as "dislocations" or "line-shifts" or "fingerprint-like" defects. Conventional defect inspection tools are either limited in resolution (brightfield optical methods) or in the area / numb...
Article
A 27nm-pitch Graphoepitaxy directed self-assembly (DSA) process targeting fin formation for FinFET device fabrication is studied in a 300mm pilot line environment. The re-designed guiding pattern of graphoepitaxy DSA process determines not only the fine DSA structures but also the fin customization in parallel direction. Consequently, the critical...
Article
EUV lithography is one of the main candidates for enabling the next generation of devices, primarily by enabling a lithography process that reduces complexity, and eventually, cost. IBM has installed the latest tool sets at the IBM EUV Center of Excellence in Albany to accelerate EUV lithography development for production use. Though the EUV cluste...
Article
The successful demonstration of 637 wafer exposures in 24 hours on the EUV scanner at the IBM EUV Center for Excellence in July marked the transition from research to process development using EUV lithography. Early process development on a new tool involves significant characterization, as it is necessary to benchmark tool performance and process...
Conference Paper
Full-text available
Process-induced overlay errors are a growing problem in meeting the ever-tightening overlay requirements for integrated circuit production. While uniform process-induced stress is easily corrected, non-uniform stress across the wafer is much more problematic, often resulting in non-correctable overlay errors. Measurements of the wafer geometry of f...
Patent
An alignment feature disposed on a substrate, the alignment feature including a first lithographic pattern having a first aggregate geometric center point defined by a first sub-pattern comprising alignment marks having a first sub-pattern geometric center point arranged a distance (d0) in a first direction from the first aggregate geometric center...
Article
Process-induced overlay errors are a growing problem in meeting the ever-tightening overlay requirements for integrated circuit production. Although uniform process-induced stress is easily corrected, nonuniform stress across the wafer is much more problematic, often resulting in noncorrectable overlay errors. Measurements of the wafer geometry of...
Conference Paper
This paper describes the joint development and optimization of an advanced critical dimension (CD) control methodology at IBM’s 300 mm semiconductor facility. The work is initially based on 22 nm critical level gate CD control, but the methodology is designed to support both the lithography equipment (1.35 NA scanners) and processes for 22, 20, 18,...
Patent
A wafer includes an active region and a kerf region surrounding at least a portion of the active region. The wafer also includes a target region having a rectangular shape with a width and a length greater than the width, the target region including one or more target patterns, at least one of the target patterns being formed by two sub-patterns di...
Article
Commercially available permeable supports with microporous membranes have led to significant improvements in the culture of polarized cells because they permit them to feed basolaterally and thus carry out metabolism in a more in vivo-like setting. The porous nature of these membranes enables permeability measurements of drugs or biomolecules acros...
Article
Requirements for ever tightening overlay control are driving improvements in tool set up and matching procedures, APC processes, and wafer alignment techniques in an attempt to address both systematic and non systematic sources of overlay error. Thermal processes used in semiconductor manufacturing have been shown to have drastic and unpredictable...
Article
The work reviewed will describe a particular effort in the area of overlay matching based on the BaseLiner™ package marketed by ASML. BaseLiner relies on the concept of Scanner Baseline Constants (SBCs). Traditionally, optical lithography systems are controlled by many numerical parameters known as Machine Constants (MCs). MCs are typically generat...
Article
To keep pace with the overall dimensional shrink in the industry, overlay capability must also shrink proportionally. Unsurprisingly, overlay capability < 10 nm is already required for currently nodes in development, and the need for multi-patterned levels has accelerated the overlay roadmap requirements to the order of 5 nm. To achieve this, many...
Article
Optical properties (n&k) of the material films under measurement are commonly assumed invariant and fixed in scatterometry modeling. This assumption keeps the modeling simple by limiting the number of floating parameters in the model. Such scatterometry measurement has the potential to measure with high precision some of the profile parameters (CD,...
Article
With the introduction of double patterning, overlay capability below 5nm is required for optical lithography density scaling to the 22nm node and beyond. Commensurate overlay metrology must enable dense sampling of all patterned area to control single-nanometer systematic sources of error among an increasing number of device layers. This translates...
Article
The ever shrinking lithography process window requires us to maximize our process window and minimize tool-induced process variation, and also to quantify the disturbances to an imaging process caused upstream of the imaging step. Relevant factors include across-wafer and wafer-to-wafer film thickness variation, wafer flatness, wafer edge effects,...
Article
Continued lithographic pattern density scaling depends on aggressive overlay error reduction.1,2 Double patterning processes planned for the 22nm node require overlay tolerances below 5 nm; at which point even sub-nanometer contributions must be considered. In this paper we highlight the need to characterize and control the single-layer matching am...
Article
Many factors are driving a significant tightening of the overlay budget for advanced technology nodes, e.g. 6nm [mean + 3sigma] for 22nm node. Exposure tools will be challenged to support this goal, even with tool dedication. However, tool dedication has adverse impact on cycle time reduction, line productivity and cost issues. There is a strong de...
Article
Environmentally benign supercritical carbon dioxide (scCO2) has been utilized as an “ecologically responsible” solvent for a wide variety of applications. However, nonpolar scCO2 is generally a very poor solvent for polar polymers which limits its use as a processing solvent in high resolution photolithography. In this paper, we report the synthesi...
Article
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring quantitatively their molecular mass distribution with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A mathematical method for polydisperse materials is described that creates a calibration curve to correct...
Article
We have examined four molecular glass (MG) materials that show promise as photoresists for extreme-ultraviolet (EUV) lithography. These glass-forming materials were investigated by proton and 13C solid state nuclear magnetic resonance (NMR) techniques in the bulk state as pure materials and as mixtures with (5 or 10) % by mass of the photoacid gene...
Article
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring, quantitatively, their molecular mass distribution with matrix-assisted laser desorption/ionization time of flight mass spectrometry. A mathematical method for polydisperse materials is described that creates a calibration curve to corre...
Article
The success of the semiconductor industry is based on the ability to fabricate hundreds of millions of devices on a single chip. In order to fulfill the ever-shrinking feature sizes, the industry requires new patternable materials in order to operate in the sub-50 nm regime. Molecular glass (MG) resists are a new type of patterning material that ha...
Article
A new type of acid-catalyzed, chain-scission polymeric system is reported based on main-chain acetal linkages and designed for solubility selectivity in supercritical (sc) CO2. These low-molecular-weight polymer segments, formed by the stepwise polymerization of divinyl ethers and dihydroxy-based monomers, are linked together to render these indivi...
Article
The thermal properties and scCO2 solubility of ring-type MG photoresists based on calix[4]resorcinarene was investigated. A selection of substituents was introduced to the para position of the bridging phenyl group. The structural similarity of calix[n] and calix[4]-resorcinarene to well-known novolac- and poly(hydroxystyrene) (PHOST)-based resists...
Article
Full-text available
The ability of the semiconductor industry to reduce device dimensions below 45 nm is hindered by limitations in both resist material and processing techniques. High resolution and sensitivity along with low line edge roughness are key requirements of next generation resist materials. In order to meet future demands of the semiconductor industry, ne...
Article
Full-text available
Because of their small size, molecular glasses have the potential for scCO2 solubility while still showing performance equal to polymer photoresists. In addition, because of their small, discrete structures, these materials can possess uniform dissolution rates and lower line-edge roughness compared to traditional polymer resists. For these materia...
Article
Full-text available
Current extreme ultraviolet (EUV) photoresist materials do not yet meet performance requirements on exposure-dose sensitivity, line-width roughness, and resolution. In order to quantify how these trade-offs are related to the materials properties of the resist and processing conditions, advanced measurements and fundamental studies are required tha...
Article
Full-text available
We have examined four molecular glasses (MGs) which are candidates for EUV photoresist formulations. These derivatized glasses, and their unprotected precursors, were investigated by both proton and 13C solid state NMR techniques in the bulk state as pure materials and as mixtures with 5 or 10 % by mass of the photoacid generator (PAG), triphenyl s...
Article
It has been recently postulated that sub-22 nm photolithography with polymeric photoresists has reached a materials design barrier due to its large molecular mass and distribution. In this argument, the "pixel" size, which is related to the smallest molecular unit, determines the feature fidelity and resolution of the lithographic process. This hyp...
Article
Photoresists based on molecular glasses are gaining more and more importance as resist material to replace polymer based photoresist. In addition environmental issues have to be considered in the long-term. Therefore the paper describes novel negative photoresists containing a ternary mixture of a glassy low molecular functional polyphenol where th...
Article
In this paper, we report the synthesis and characterization of a family of phenolic molecular glasses with variable size and branch architecture. This research is aimed at providing an improved understanding of the relationship between the structural variations of these phenolic photoresist materials and their thermal properties. In particular, the...
Article
The dissolution characteristics of small molecule photoresist films in supercritical CO2 are measured using laser interferometry. These small molecule photoresists, referred to as molecular glasses, have shown impressive CO2 solubility in recent reports, and in order to understand this behavior the structure–property relationships that control thin...
Article
A negative tone photoresist film, consisting of a molecular glass, a photoacid generator, and an acid labile crosslinker, was prepared by physical vapor deposition, a solvent-free process. Subsequent to deposition, the coevaporated monomers were exposed using 365 nm radiation, subjected to a post exposure bake step, and developed in aqueous base to...
Article
In this contribution, we describe our efforts to develop novel chemically amplified molecular glass (MG) photoresists based on bulky phenol structures. In contrast to conventional polymeric materials, MG resists possess distinct advantages, such as smaller molecular size and uniformity in composition. A number of compounds which possess rigid aroma...