Bottom-up alternative lithographic masks from directed self-assembly systems have been extending the limits of critical
dimensions in a cost-effective manner although great challenges in controlling defectivity remain open. Particularly,
defectivity and dimensional metrology are two main challenges in lithography due to the increasing miniaturisation of
circuits. To gain insights about the percentage of alignment, defectivity and order quantification, directed self-assembly
block copolymer fingerprints were investigated via an image analysis methodology. Here we present the analysis of
hexagonal phase of polystyrene-b-polydimethylsiloxane (PS-b-PDMS) forming linear patterns in topological substrates.
From our methodology, we have performed dimensional metrology estimating pitch size and error, and the linewidth of
the lines was estimated. In parallel, the methodology allowed us identification and quantification of typical defects
observable in self-assembly, such as turning points, disclination or branching points, break or lone points and end points.
The methodology presented here yields high volume statistical data useful for advancing dimensional metrology and
defect analysis of self- and directed assembly systems.
Multilevel controllable nanoimprint driven molecular orientation has been obtained in thin films of block copolymer polystyrene-b-polyethylene oxide( PS-b-PEO) by means of solvent vapours assisted nanoimprint lithography (SAIL). The NIL setup using solvent vapours was capable of imprinting nanoscale features over a large area and simultaneously annealing PS-b-PEO thin films. A line pattern stamp was replicated in the BCP film in over a large area with a high resolution registry, and was also observed that the PS-b-PEO film exhibited microphase segregation in the residual layer exhibits a nanodot array from showing hexagonally packed PEO dots in the PS matrix, with a diameter of 20 nm with 40 nm pitch. The order of the hexagonally arranged nanodot lattice seen in the nanodots array was quantified from SEM images using by the opposite partner method from SEM images analysis and compared with to conventionally solvent annealed BCP films, demonstrating an improvement of the ordering of up to 50%. Grazing-incidence small-angle X-ray scattering (GISAXS) study demonstrates the excellent fidelity of the pattern transfer and confirms the periodicity of the BCP in the mesas. In addition, applying the SAIL methodology to BCP thin films in nanopatterned silsequioxane substrates, it was possible to obtain multilevel structures decorated with the BCP microphase segregation. The SAIL technique is a versatile and robust platform to obtain complex high density periodic nanostructures, particularly for second generation block copolymers directed self-assembly.
The line patterns obtained by the self-assembly of the block copolymer (BCP) polystyrene-b-polyethylene oxide (PS-b-PEO)
was investigated. The hexagonal PS-b-PEO 42k-11.5k in a thin film was solvent annealed in a chlorophorm saturated
atmosphere for three different annealing times. The microphase segregation of this BCP returned 18nm cylinders of PEO
through the PS matrix, with an approximately 40 n periodicity, as expected. Under chlorophorm vapours, the PEO cylinders
oriented perpendicular to the silicon substrate while increasing the annealing time. These cylinders formed linear patterns
with different alignment. To achieve insights about the percentage of alignment, defect type pareto and density, and order
quantification to compare the three annealing recipes, the samples were analysed with innovative image analysis software
specifically developed in our laboratory to identify elements and defects of line arrays from block copolymer self-assembly.
From this technique, it was extracted dimensional metrology estimating pitch size and placement error, and the line-width of
the lines was estimated. Secondly, the methodology allows identification and quantification of typical defects observable in
BCP systems, such as turning points, disclination or branching points, break or lone points and end points. The defect density
and the quantification of the alignment were estimated using our technique. The methodology presented here represents a
step forward in dimensional metrology and defect analysis of BCP DSA systems and can be readily used to analyze other
lithographic or non-lithographic patterns.
Different linear patterns obtained from the directed self-assembly of the block copolymer (BCP) polystyrene-b-polyethylene oxide (PS-b-PEO) were analysed and compared. The hexagonal phase PS-b-PEO in a thin film exhibits linear pattern morphology, by conventional solvent annealing in an atmosphere saturated in chloroform. The surface energy of the silicon substrates was varied using surface functionalization of a self-assembly monolayer (SAM) and a polymer brush, chosen to investigate the influence of the surface energy on the self-assembly of the BCP. The linear patterns formed were analyzed with innovative image analysis software specifically developed in our laboratory to identify elements and defects of line arrays from block copolymer self-assembly. The technique starts by performing dimensional metrology to calculate the pitch size and estimate the linewidth of the lines. Secondly, the methodology allows identification and quantification of typical defects observable in BCP systems, such as turning points, disclination or branching points, break or lone points and end points. The defect density and the quantification of the alignment were estimated using our technique. The methodology presented here represents a step forward in dimensional metrology and defect analysis of BCP DSA systems and can be readily used to analyze other lithographic or non-lithographic patterns.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.