Orientation control of thin film nanostructures derived from block copolymers (BCPs) are of great interest for various emerging technologies like separation membranes, nanopatterning, and energy storage. While many BCP compositions have been developed for these applications, perpendicular orientation of these BCP domains is still very challenging to achieve. Herein we report on a new, integration-friendly approach in which small amounts of a phase-preferential, surface active polymer (SAP) was used as an additive to a polycarbonate-containing BCP formulation to obtain perpendicularly oriented domains with 19 nm natural periodicity upon thermal annealing. In this work, the vertically oriented BCP domains were used to demonstrate next generation patterning applications for advanced semiconductor nodes. Furthermore, these domains were used to demonstrate pattern transfer into a hardmask layer via commonly used etch techniques and graphoepitaxy-based directed self-assembly using existing lithographic integration schemes. We believe that this novel formulation-based approach can easily be extended to other applications beyond nanopatterning.

To extend the scaling beyond the most widely used block copolymer (BCP), poly(styrene)-block-poly(methyl methacrylate) (PS-b-PMMA), a new organic high-chi BCP based was developed. Polystyrene-b-polytrimethylene carbonate (PS-b-PTMC) BCP was synthesized using ring opening polymerization (ROP) of trimethylene carbonate from hydroxy-functional polystyrene (PS-OH) with diazabicyclo[5.4.0]undec-7-ene (DBU) as the base catalyst. The resulting BCP was characterized by H-1 nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) to confirm the complete chain extension of the polystyrene macroinitiator. For the DBU catalyzed BCP, the GPC trace revealed a trimodal distribution indicating the presence of coupling product and homo-PTMC impurity. Using purification techniques, homo-PTMC impurity was isolated to afford purified BCP. Thin-film morphologies of the non-purified and the purified BCPs on poly(methyl methacrylate) (PMMA) coated substrates followed by short thermal annealing were characterized using atomic force microscopy (AFM) analysis. The non-purified BCP showed island morphology with a step-height of 17 nm whereas the purified PS-b-PTMC showed a flat film with parallel cylinders of 16.4 nm pitch row-to-row distance. The ability for the PS-b-PTMC to self-assemble below 20-nm pitch resolution confirms the high interaction parameter, chi, between the PS and PTMC blocks and is a promising candidate as a high-chi BCP for directed self-assembly (DSA) application.

Diminishing error tolerance renders the customization of patterns created through directed self-assembly (DSA) extremely challenging at tighter pitch. A self-aligned customization scheme can be achieved using a hybrid prepattern comprising both organic and inorganic regions that serves as a guiding prepattern to direct the self-assembly of the block copolymers as well as a cut mask pattern for the DSA arrays aligned to it. In this paper, chemoepitaxy-based self-aligned customization is demonstrated using two types of organic-inorganic prepatterns. CHEETAH prepattern for "CHemoepitaxy Etch Trim using a self-Aligned Hardmask" of preferential hydrogen silsesquioxane (HSQ, inorganic resist), non-preferential organic underlayer is fabricated using electron beam lithography. Customized trench or hole arrays can be achieved through co-transfer of DSA-formed arrays and CHEETAH prepattern. Herein, we also introduce a tone-reversed version called reverse-CHEETAH ( or rCHEETAH) in which customized line segments can be achieved through co-transfer of DSA-formed arrays formed on a prepattern wherein the inorganic HSQ regions are non-preferential and the organic regions are PMMA preferential. Examples of two-dimensional self-aligned customization including 25nm pitch fin structures and an 8-bar "IBM" illustrate the versatility of this customization scheme using rCHEETAH.

To extend scaling beyond poly(styrene-b-methyl methacrylate) (PS-b-PMMA) for directed self-assembly (DSA), high quality organic high-x block copolymers (HC series) were developed and applied to implementation of sub-10 nm L/S DSA. Lamellae-forming block copolymers (BCPs) of the HC series showed the ability to form vertically oriented polymer domains conveniently with the in-house PS-r-PMMA underlayers (AZEMBLY EXP NLD series) without the use of an additional topcoat. The orientation control was achieved with low bake temperatures (≤200 °C) and short bake times (≤5 min). Also, these process-friendly materials are compatible with existing 193i-based graphoepitaxy and chemoepitaxy DSA schemes. In addition, it is notable that 8.5 nm organic lamellae domains were amenable to pattern development by simple dry etch techniques. These successful demonstrations of high-x L/S DSA on 193i-defined guiding patterns and pattern development can offer a feasible route to access sub-10 nm node patterning technology.

We continue to study the feasibility of using Directed Self Assembly (DSA) in extending optical lithography for High Volume Manufacturing (HVM). We built test masks based on the mask datatprep flow we proposed in our prior year’s publication [1]. Experimental data on circuit-relevant fin and via patterns based on 193nm graphoepitaxial DSA are demonstrated on 300mm wafers. With this computational lithography (CL) flow we further investigate the basic requirements for full-field capable DSA lithography. The first issue is on DSA-specific defects which can be either random defects due to material properties or the systematic DSA defects that are mainly induced by the variations of the guiding patterns (GP) in 3 dimensions. We focus in studying the latter one. The second issue is the availability of fast DSA models to meet the full-chip capability requirements in different CL component’s need. We further developed different model formulations that constitute the whole spectrum of models in the DSA CL flow. In addition to the Molecular Dynamic/Monte Carlo (MD/MC) model and the compact models we discussed before [2], we implement a 2D phenomenological phase field model by solving the Cahn-Hilliard type of equation that provide a model that is more predictive than compact model but much faster then the physics-based MC model. However simplifying the model might lose the accuracy in prediction especially in the z direction so a critical question emerged: Can a 2D model be useful fro full field? Using 2D and 3D simulations on a few typical constructs we illustrate that a combination of 2D mode with pre-characterized 3D litho metrics might be able to approximate the prediction of 3D models to satisfy the full chip runtime requirement. Finally we conclude with the special attentions we have to pay in the implementation of 193nm based lithography process using DSA.

The directed self-assembly (DSA) of block copolymers (BCP) is an emerging resolution enhancement tool that can multiply or subdivide the pitch of a lithographically defined chemical or topological pattern and is a resolution enhancement candidate to augment conventional lithography for patterning sub-20 nm features. Continuing the development of this technology will require an improved understanding of the polymer physics involved as well as experimental confirmation of the simulations used to guide the design process. Both of these endeavors would be greatly facilitated by a metrology, which is capable of probing the internal morphology of a DSA film. We have developed a new measurement technique, resonant critical-dimension small-angle X-ray scattering (res-CDSAXS), to evaluate the 3D buried features inside the film. This is an X-ray scattering measurement where the sample angle is varied to probe the 3D structure of the film, while resonant soft X-rays are used to enhance the scattering contrast. By measuring the same sample with both res-CDSAXS and traditional CDSAXS (with hard X-rays), we are able to demonstrate the dramatic improvement in scattering obtained through the use of resonant soft X-rays. Analysis of the reciprocal space map constructed from the res-CDSAXS measurements allowed us to reconstruct the complex buried features in DSA BCP films. We studied a series of DSA BCP films with varying template widths, and the internal morphologies for these samples were compared to the results of single chain in mean-field simulations. The measurements revealed a range of morphologies that occur with changing template width, including results that suggest the presence of mixed morphologies composed of both whole and necking lamella. The development of res-CDSAXS will enable a better understanding of the fundamental physics behind the formation of buried features in DSA BCP films.

The first fully integrated SOI device using 42nm-pitch directed self-assembly (DSA) process for fin formation has been demonstrated in a 300mm pilot line environment. Two major issues were observed and resolved in the fin formation process. The cause of the issues and process optimization are discussed. The DSA device shows comparable yield with slight short channel degradation which is a result of a large fin CD when compared to the devices made by baseline process. LER/LWR analysis through the DSA process implied that the 42nm-pitch DSA process may not have reached the thermodynamic equilibrium. Here, we also show preliminary results from using scatterometry to detect DSA defects before removing one of the blocks in BCP.

EUV insertion timing for High Volume Manufacturing is still an uncertainty due to source power and EUV mask infrastructure limitations. Directed Self Assembly (DSA) processes offer the promise of providing alternative ways to extend optical lithography cost-effectively for use in the 10nm node and beyond. The goal of this paper is to look into the technical prospect of DSA technology, particularly in the computational and DFM area. We have developed a prototype computational patterning toolset in-house to enable an early Design-Technology Co-Optimization to study the feasibility of using DSA in patterning semiconductor devices and circuits. From this toolset we can identify the set of DSA specific design restrictions specific to a DSA process and plan to develop a novel full chip capable computational patterning solution with DSA. We discuss the DSA Computational Lithography (CL) infrastructure using the via and fin layers as examples. Early wafer data is collected from the DSA testmask that was built using these new toolsets. Finally we discuss the DSA ecosystem requirements for enabling DSA lithography and propose how EDA vendors can play a role in making DSA Lithography (DSAL) a full-chip viable technology for multiple process layers.

The patterning capability of the directed self-assembly (DSA) of a 42nm-pitch block copolymer on an 84nm-pitch guiding pattern was investigated in a 300mm pilot line environment. The chemo-epitaxy guiding pattern was created by the IBM Almaden approach using brush materials in combination with an optional chemical slimming of the resist lines. Critical dimension (CD) uniformity, line-edge/line-width roughness (LER/LWR), and lithographic process window (PW) of the DSA process were characterized. CD rectification and LWR reduction were observed. The chemical slimming process was found to be effective in reducing pattern collapse, hence, slightly improving the DSA PW under over-dose conditions. However, the overall PW was found to be smaller than without using the slimming, due to a new failure mode at under-dose region.

A photomask design flow for generating guiding patterns used in graphoepitaxial DSA processes is proposed and tested. In this flow, a new fast DSA model is employed for DSA structure verification. The execution speed and accuracy of the fast model were benchmarked with our previously reported Monte Carlo method. We demonstrated the process window verification using the OPC/DSA flow with the fast DSA model and compared this with experimental results in the guiding patterns simulated by e-beam lithography.

The main concern for the commercialization of directed self-assembly (DSA) for semiconductor manufacturing continues to be the uncertainty in capability and control of defect density. Our research investigates the defect densities of various DSA process applications in the context of a 300mm wafer fab cleanroom environment; this paper expands substantially on the previously published DSA defectivity study(1) by reporting a defect density process window relative to chemical epitaxial pre-pattern registration lines; as well as investigated DSA based contact hole shrinking and report critical dimension statistics for the phase separated polymers before and after etch, along with positional accuracy measurements and missing via defect density.

Nanogel star polymers are developed as a new route for the formation of dual-mode nanoparticle systems for applications in the areas of synergistic therapeutic delivery, imaged therapeutic delivery, and dual-mode bioimaging agents. These extremely uniform, structurally versatile, water-soluble, unimolecular organic nanoparticles with tunable polyvalency and functionality are preprogrammed to upload different types of complex functional macromolecules spontaneously.

Directed self-assembly is an emerging technology that to-date has been primarily driven by research efforts in university and corporate laboratory environments. Through these environments, we have seen many promising demonstrations of forming self-assembled structures with small half pitch (<15 nm), registration control, and various device-oriented shapes. Now, the attention turns to integrating these capabilities into a 300mm pilot fab, which can study directed self-assembly in the context of a semiconductor fabrication environment and equipment set. The primary aim of this study is to create a 300mm baseline process of record using a 12nm half-pitch PS-b-PMMA lamellae block copolymer in order to establish an initial measurement of the defect density due to inherent polymer phase separation defects such as dislocations and disclinations.

As an alternative technique, electroless deposition is gaining interest due to its simplicity (solution-based process, no complex instrumentation), economical aspect, and effectiveness to form certain desired film thicknesses and morphologies on a wide variety of substrates. This work describes the use of water-soluble, polyvalent star polymer templates to form spontaneous self-limiting monolayers on complimentary functionalized substrates that act as efficient adhesion layers for the electroless deposition of thin gold films. The resulting gold films display outstanding thickness control, uniformity, reproducibility, and plasmon resonance generation, as evaluated by Rutherford backscattering spectroscopy (RBS), surface plasmon resonance (SPR) spectroscopy, and atomic force microscopy (AFM). The adaptation of this technique to the formation of core-shell gold nanoparticles was also shown to be feasible. The synthesized star polymer-templated gold nanoshells display a tunable NIR absorption depending on their size. By utilizing star polymers as templates, other materials such as drugs or chromophores can be effortlessly embedded inside the star polymer via self-assembled occlusion complex formation. This ability coupled with the efficacy of gold nanoshells in absorbing NIR light and transferring the light energy as heat to their surrounding environment can lead to an integrated form of imaging contrast, drug-delivery system, and photothermal ablation agent.