Two-Dimensional Pattern Formation Using Graphoepitaxy of PS-b-PMMA Block Copolymers for Advanced FinFET Device and Circuit Fabrication

Abstract

Directed self-assembly (DSA) of lamellar phase block-co-polymers (BCPs) can be used to form nanoscale line-space patterns. However, exploiting the potential of this process for circuit relevant patterning continues to be a major challenge. In this work, we propose a way to impart two-dimensional pattern information in graphoepitaxy-based lamellar phase DSA processes by utilizing the interactions of the BCP with the template pattern. The image formation mechanism is explained through the use of Monte Carlo simulations. Circuit patterns consisting of the active region of Si FinFET transistors, referred to as Si "fins", were fabricated to demonstrate the applicability of this technique to the formation of complex patterns. The quality of the Si fin features produced by this process was validated by demonstrating the first functional DSA-patterned FinFET devices with 29 nm-pitch fins.

Enabling complex nanoscale pattern customization using directed self-assembly

“…Variability in the pattern transfer and pattern tone inversion steps independent of the DSA process were observed. High yield of the tone-inverted DSA structures can be achieved by proper co-optimization of the material stack, etch and fill processes, using tooling typically available for high-volume semiconductor manufacturing, as exemplified by Tsai et al 21,41 Image analysis. SEM images were obtained using a Leo 1550 field emission SEM, and image analysis was performed using ImageJ.…”

“…The directed self-assembly (DSA) of BCP thin films using chemical [3][4][5][6][7][8] or topographical [9][10][11][12][13][14][15][16] templates to impose long-range order and registration on the BCP domains has garnered increased interest in recent years as a means to enhance lithographic resolution by multiplying the feature density [5][6][7][8][13][14][15] and rectifying pattern non-uniformity or imperfections 5,6,17,18 of lithographically defined templates. Selective removal or alteration of one block then creates a mask that may be combined with other manufacturing techniques to fabricate devices such as patterned magnetic recording media 19 , silicon nanowire transistors 20 or FinFETs 21 .…”

Direct Self-Assembly for Non-Periodic Designs

“…A conventional approach to include non-periodic features in the periodic DSA patterns is the use of cut/block masks. For example, the silicon fins required for the FinFET device have been fabricated by cutting the DSA lamellae into groups of line segments [4][5][6]. Recently, Doerk et al have demonstrated a new DSA flow for fabricating an arbitrary design of patterns without the cutting process ( Fig.…”

Interfacial Layers with Photoswitching Surface Energy for Block Copolymer Alignment and Directed Self-Assembly

“…Furthermore, the lateral alignment of BCP domains into device oriented structures, or directed self-assembly (DSA), must be tailored for different applications in the semiconductor and data storage industries. For example, lamellar-forming BCPs are useful for patterning both FinFETS [2] and bitpatterned media [3] but the targeted lateral arrangement of DSA patterns and associated processing protocols can vary significantly.…”