Integration of nanoimprint lithography with block copolymer directed self-assembly for fabrication of a sub-20 nm template for bit-patterned media

Abstract

We propose a novel strategy to integrate the nanoimprint lithography (NIL) technique with directed self-assembly (DSA) of block copolymer (BCP) for providing a robust, high-yield, and low-defect-density path to sub-20 nm dense patterning. Through this new NIL-DSA method, UV nanoimprint resist is used as the DSA copolymer pre-pattern to expedite the DSA process. This method was successfully used to fabricate a 1.0 Td in(-2) servo-integrated nanoimprint template for bit-patterned media (BPM) application. The fabricated template was used for UV-cure NIL on a 2.5-inch disk. The imprint resist patterns were further transferred into the underlying CoCrPt magnetic layer through a carbon hard mask using ion beam etching. The successful integration of the NIL technique with the DSA process provides us with a new route to BPM nanofabrication, which includes the following three major advantages: (1) a simpler and faster way to implement DSA for high-density BPM patterning; (2) a novel method for fabricating a high-quality dot pattern template through an iterative imprint-DSA-template procedure; and (3) an uncomplicated integration scheme for implementing non-periodic servo features with BCP patterns, thus accelerating the transition of moving the DSA technique from laboratory research to the BPM manufacturing environment.

Fabrication of servo-integrated template for 1.5 Teradot/inch2bit patterned media with block copolymer directed assembly

“…It can be done in one-single DSA step if the cylinder-forming BCP film, such as PS-b-PMMA BCP film, is used in both the data area and the servo area, as previously reported. 24 However, it has been proven that PS-b-PDMS has a higher Flory-Huggins interaction parameter χ value of 0.26 than that of other BCP materials, such as PS-b-PMMA of 0.06. With the commercially available cylinder-forming PS-b-PMMA BCP material, the highest BCP density with the lowest molecular weight is about 1.3 Td∕in: 2 .…”

Rapid shear alignment of sub-10 nm cylinder-forming block copolymer films based on thermal expansion mismatch

“…Step 4: the final PDMS nanopattern (green lines) remained on the substrate after CF 4 and O 2 reactive ion etch (RIE) processes.…”

“…Directed self-assembly of block copolymer (BCP) microdomains in thin films has been used to enhance the correlation length of the periodic patterns for a wide variety of applications, including integrated electronics [1][2][3], data storage [4], photonic materials [5], and bio-functionalized surfaces [6]. The limited correlation length of BCP microdomain arrays has been overcome through engineering methods to produce both longrange order and local control over patterns.…”

CMOS-Compatible Top-Down Fabrication of Periodic SiO2 Nanostructures using a Single Mask

“…Some periodic nanostructures of Si and SiO2 have been successfully fabricated with this technology in recent years [15][16][17]. Despite the numerous advantages and fruitful achievements of patterning nanostructures offered by the self-assembly, there are some challenges to restrict the patterning transfer of block copolymer patterns to various substrate materials.…”

“…In this case, there have been some incompatible processes with currently mature semiconductor nanofabrication techniques used to fabricate various nanostructures. Most frequently, the metal film such as Cr or Au serving as an etch mask is very necessarily required to reduce the close dependence of dry etch process on the block copolymer, and also a lift-off process is generally required to define different patterns dependent on various specific requirements [17][18][19][20]. This makes the self-assembly difficult to be applied to currently standard semiconductor equipment, limiting mass-production and readily convenient integration into practical CMOS devices.…”