A New Materials-based Pitch Division Technique

Gu, Xinyu; Bates, Christopher M.; Cho, Younjin; Costner, Elizabeth A.; Marzuka, Fernando; Nagai, Takeharu; Ogata, Toshiyuki; Shi, Chuan; Sundaresan, Arun Kumar; Turro, Nicholas J.; Bristol, Robert; Zimmerman, Paul; Wilson, Calum

doi:10.2494/photopolymer.22.773

Cited by 8 publications

(14 citation statements)

References 11 publications

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“…To study the entire sequential two-step base generation as outlined in Scheme 1, acetonitrile solutions of 1 were irradiated at 254 nm and analyzed by HPLC (Supporting Information, Figure S11). Using authentic samples and quantitative HPLC calibration, the concentrations of the major product (3) and intermediate (2) were determined. Figure 5 shows the concentrations of 1, 2, and 3 with increasing photolysis time.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Study of a Two-Stage Photobase Generator for Photolithography in Microelectronics

Turro

Jockusch

et al. 2012

J. Org. Chem.

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The investigation of the photochemistry of a two-stage photobase generator (PBG) is described. Absorption of a photon by a latent PBG (1) (first step) produces a PBG (2). Irradiation of 2 in the presence of water produces a base (second step). This two-photon sequence (1 + hν → 2 + hν → base) is an important component in the design of photoresists for pitch division technology, a method that doubles the resolution of projection photolithography for the production of microelectronic chips. In the present system, the excitation of 1 results in a Norrish type II intramolecular hydrogen abstraction to generate a 1,4-biradiacal that undergoes cleavage to form 2 and acetophenone (Φ ∼ 0.04). In the second step, excitation of 2 causes cleavage of the oxime ester (Φ = 0.56) followed by base generation after reaction with water.

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Section: ■ Results and Discussionmentioning

confidence: 99%

“…This leads to a division of the pitch and doubling of the resolution. 2,3 However, line edge roughness of the developed resist features prevents commercial implementation of pitch division. 3 It has been proposed that the line edge roughness can be improved by creating a delay in the onset of base generation.…”

Section: ■ Introductionmentioning

confidence: 99%

Study of a Two-Stage Photobase Generator for Photolithography in Microelectronics

Turro

Jockusch

et al. 2012

J. Org. Chem.

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“…The proof-of-concept has been published in the previous paper [1,2] and demonstrated by others [1]. Forty five nm half-pitch (HP) patterns were produced using a 90nm HP mask, but the image had line edge roughness (LER) that does not meet requirements.…”

Section: Introductionmentioning

confidence: 99%

“…We hope to develop a technique that would provide access to the 22 nm and 16 nm nodes, which does not require extra processing steps or new capital equipment. A material based pitch division lithography proposed by our group in 2009 [2] would fulfill that goal. The pitch division technique requires only a single exposure to create pitch divided patterns without extra processing steps.…”

Section: Introductionmentioning

confidence: 99%

Photobase generator enabled pitch division: a progress report

Cho

Kawakami

et al. 2011

SPIE Proceedings

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Pitch division lithography (PDL) with a photobase generator (PBG) allows printing of grating images with twice the pitch of a mask. The proof-of-concept has been published in the previous paper [1,2] and demonstrated by others [1]. Forty five nm half-pitch (HP) patterns were produced using a 90nm HP mask, but the image had line edge roughness (LER) that does not meet requirements. Efforts have been made to understand and improve the LER in this process. Challenges were summarized toward low LER and good performing pitch division. Simulations and analysis showed the necessity for an optical image that is uniform in the z direction in order for pitch division to be successful. Two-stage PBGs were designed for enhancement of resist chemical contrast. New pitch division resists with polymer-bound PAGs and PBGs, and various PBGs were tested. This paper focuses on analysis of the LER problems and efforts to improve patterning performance in pitch division lithography.

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“…Pitch doubling lithography (PDL) using a dual-tone photoresist for pitch division assisted by photobase generator (PBG) was recently presented. 1 By using dose-dependent base quenching to control the net acid concentration in resist films, the resist solubility response can have twice the frequency of the aerial image. In the low dose region (below E 0 ) the amount of base produces is less than the acid (k b << k a ) hence, the film behaves like a positive tone resist.…”

Section: Introductionmentioning

confidence: 99%

Polymer-bound photobase generators and photoacid generators for pitch division lithography

Cho

Hagiwara

et al. 2011

SPIE Proceedings

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The semiconductor industry is pursuing several process options that provide pathways to printing images smaller than the theoretical resolution limit of 193 nm projection scanners. These processes include double patterning, side wall deposition and pitch division. Pitch doubling lithography (PDL), the achievement of pitch division by addition of a photobase generator (PBG) to typical 193 nm resist formulations was recently presented.1 Controlling the net acid concentration as a function of dose by incorporating both a photoacid generator (PAG) and a PBG in the resist formulation imparts a resist dissolution rate response modulation at twice the frequency of the aerial image. Simulation and patterning of 45 nm half pitch L/S patterns produced using a 90 nm half pitch mask were reported.2 Pitch division was achieved, but the line edge roughness of the resulting images did not meet the current standard. To reduce line edge roughness, polymer bound PBGs and polymer bound PAGs were investigated in the PDL resist formulations. The synthesis, purification, analysis, and functional performance of various polymers containing PBG or PAG monomers are described herein. Both polymer bound PBG with monomeric PAG and polymer bound PAG with monomeric PBG showed a PDL response. The performance of the polymer bound formulations is compared to the same formulations with small molecule analogs of PAG and PBG.

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A New Materials-based Pitch Division Technique

Cited by 8 publications

References 11 publications

Study of a Two-Stage Photobase Generator for Photolithography in Microelectronics

Study of a Two-Stage Photobase Generator for Photolithography in Microelectronics

Photobase generator enabled pitch division: a progress report

Polymer-bound photobase generators and photoacid generators for pitch division lithography

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