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We report a method for the directed self-assembly (DSA) of block copolymers (BCPs) in which a first BCP film deploys homopolymer brushes, or "inks", that sequentially graft onto the substrate's surface via the interpenetration of polymer molecules during the thermal annealing of the polymer film on top of existing polymer brushes. By selecting polymer "inks" with the desired chemistry and appropriate relative molecular weights, it is possible to use brush interpenetration as a powerful technique to generate self-registered chemical contrast patterns at the same frequency as that of the domains of the BCP. The result is a process with a higher tolerance to dimensional and chemical imperfections in the guiding patterns, which we showcase by implementing DSA using homopolymer brushes for the guiding features as opposed to more robust cross-linkable mats. We find that the use of "inks" does not compromise the line width roughness, and the quality of the DSA as a lithographic mask is verified by implementing a robust "dry lift-off" pattern transfer.

With the technological development and progresses of the semiconductor industry， chip manufacturing is stepping forward to the advanced technology nodes under the impetus of Moore's Law. Meanwhile，the corresponding advanced materials for lithography are highly desired to satisfy the rapid development of advanced lithographic patterning. This review focuses on the composition and performances of materials for lithography. The photoresist from ultraviolet，deep ultraviolet，and extreme ultraviolet light as well as semiconducting photoresist and materials for directed self-assembly （DSA） are systematically summarized. Subsequently，the current market development and requirement of materials for lithography are critically examined. Finally，after a brief summary，an outlook for the prospective studies on advanced materials for lithography and the corresponding solutions to improve the domestic market occupancy is provided [ABSTRACT FROM AUTHOR]

We leveraged the potential of high χ-low N block copolymer (BCP), namely, poly[2-(perfluorobutyl) ethyl methacrylate]- block -poly(2-vinylpyridine) (P2PFBEMA- b -P2VP), and demonstrated its utility in next-generation nanomanufacturing. By combining molecular dynamics simulations with experiments, the χ value was calculated to be as high as 0.4 (at 150 °C), surpassing similar structures. Highly ordered features suitable for application were observed, ranging in periods from 19.0 nm down to 12.1 nm, with feature sizes as small as 6 nm. Transmission electron microscopy images of the BCP solutions indicated that preformed micelles in the solution facilitated the self-assembly process of the thin film. In addition, the vertical or parallel orientation of the cylindrical structure was determined by manipulating the solvent, substrate, and annealing conditions. Finally, guided by a wide topographical template, nearly defect-free directed self-assembly (DSA) lines with a resolution of 8 nm were achieved, highlighting its potential practical application in DSA lithography technology.

Contact hole (CH) patterning by directed self-assembly (DSA) of polystyrene-b-polymethylmethacry-late (PS-b-PMMA) block copolymers (BCPs) is extensively studied. Based on statistical analysis of defectivity and CD measurements after DSA, a process window (PW) for CH shrink is experimentally determined as a function of guiding pattern dimensions and BCP molecular weights corresponding to BCP natural periods. This PW permits to define the suitable BCP molecular weight and the best guiding CD ranges required to achieve a desired DSA hole CD within a specific tolerance. As an example, for a DSA hole CD targeted at 19.5 nm with 10% tolerance, circular guiding patterns of 52 nm CD with 20% guiding CD latitude are needed using a 35-nm-natural-period cylindrical BCP. Furthermore, it is shown that the CH shrink PW is also dependent on the guiding pattern density and the DSA process conditions such as the self-assembly annealing and the spin coating conditions. The study also highlights an interesting property of commensurability between guiding pattern dimensions and BCP's natural period that governs the DSA CH patterning for both CH shrink and CH doubling configurations. This permits one to predict the guiding pattern dimensions needed for CH patterning by DSA using a given BCP of known natural period. [ABSTRACT FROM AUTHOR]

Resistive electrical test structures have been designed to enable the characterization of optical proximity correction (OPC) applied to a right-angled corner in a conducting track. The OPC consists of square serifs that are either added to the outside corner or subtracted from the inner corner. Varying degrees of OPC can be applied by changing the size of the square serif or by changing the amount by which it encroaches on or protrudes from the corner. A prototype test mask has been fabricated that contains test structures suitable for on-mask electrical measurement. The same mask was used to print the test pattern in polysilicon and aluminium using an i-line lithography tool and results from these structures clearly show that OPC has an impact on the resistance of the final printed features. In particular, the level of corner rounding is dependent upon the dimensions of the serifs employed and the measured resistance can be used to characterize the effects of different levels of OPC applied to the inner corners. [ABSTRACT FROM PUBLISHER]

For bit patterned media (BPM) applications, while significant progress has recently been made in demonstrating high-resolution dot patterning using e-beam direct writing, and followed by the successful imprint process, many serious issues in fabrication still remain. This paper will only discuss the key challenges in the BPM lithography, including 1) the commercial availability of a high-resolution rotating stage e-beam system; 2) the approach and limitation of directed polymer self-assembly for resist pattern quality improvement and resolution enhancement; 3) the difficulties and limitations in the fabrication and replication of a 1 x template with a density beyond 1 Tbit per square inch (Tb/in2), while the defectivity, lifetime, and damage of the template are still questionable; 4) the tight requirements of size uniformity and placement accuracy; and 5) the needs of advanced metrology associated with the very small dot size and defect characterization. In this paper, we will address the above challenges and present some experimental data along with possible solutions for the challenges. [ABSTRACT FROM AUTHOR]

This paper compares electrical, optical, and atomic force microscope (AFM) measurements of critical dimension (CD) made on a chrome on quartz photomask. Test structures suitable for direct, on-mask electrical probing have been measured using the above three techniques. These include cross-bridge linewidth structures and pairs of Kelvin bridge resistors designed to investigate dimensional mismatch. Overall, the results show very good agreement between the electrical measurements and those made with a calibrated CD-AFM system, while the optical metrology system overestimates the measured width. The uncertainty in each of the measurements has been considered, and for the first time an attempt has been made to describe the levels and sources of uncertainty in the electrical measurement of CD on advanced binary photomasks. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of optical and electrical techniques for critical dimension (CD) metrology on binary and alternating aperture phase-shifting masks. Measurements obtained from on-mask electrical CD structures are compared with optical measurements made using a deep ultraviolet mask metrology system. The results show that the presence of alternating phase-shifting trenches between the chrome blocking features has a detrimental effect on the optical measurements and that this effect strongly depends on the depth of the trenches. In addition, the optical metrology system appears to have problems with the measurement of the narrowest isolated features due to calibration related issues. Electrical CD measurements are seen as a way of probing the limits of optical tool calibration and for highlighting and managing the need to extend the complexity of the calibration schedule. [ABSTRACT FROM AUTHOR]

Directed self-assembly (DSA) of block copolymer (BCP) thin films, especially with density multiplication, is one of the most promising options for further improving resolution and throughput in nanolithography. However, controlling defect density has been one of the major hurdles for many DSA applications. Both thermodynamically and kinetically, defect-free patterns favor the use of low density multiplication factors and thinner films, which undermine the promise of enhanced resolution and the formation of robust masks for pattern transfer. Here, we demonstrate a self-registered self-assembly method to enable nearly perfect DSA on loosely defined chemical patterns with high density multiplication factor. Self-registered self-assembly involves two DSA steps. In the first step, an ultrathin BCP blend film is used to obtain vanishingly low defect densities. Concurrently as the film is annealed, preloaded chemical markers separate into the different polymer blocks and graft to the substrate locking in a new chemical contrast pattern with 1:1 feature registration. After thorough removal of the blend film, the remaining self-registered chemical pattern can establish defect-free DSA of thick BCP films.