Area-selective atomic layer deposition of Al₂O₃ using inkjet-printed inhibition patterns and lift-off process

Figures & data

Figure 1. Schematic diagram of the proposed AS-ALD method using inkjet-printed ALD-inhibition test patterns and lift-off process.

Figure 2. PR dot patterns inkjet-printed with a single drop on hydrophilic tracks: (a) W_track= 60 µm, (b) W_track= 50 µm, (c) W_track= 40 µm, (d) W_track= 30 µm (W_track = hydrophilic track width between FC line patterns).

Figure 3. Inkjet-printed PR line patterns on hydrophilic tracks (W_track): (a) W_track= 60 µm; (b) W_track= 50 µm; (c) W_track= 40 µm; (d) W_track= 30 µm; (e) cross-sectional profile (W_track = a hydrophilic track width between FC line patterns).

Table 1. Ink-jetting performance for mixing ratios of PR and EL solvents.

Property		Surface
Mixing ratio	Viscosity (cP)	Tension (mN/m)	Ink-jetting
PR (100% v/v)	25.2	30.47	No jetting
50% v/v	7.5	29.26	Jetting
33% v/v	4.6	29.62	Jetting
EL Solvent (0% v/v)	3.1	29.57	Jetting

Figure 4. PR patterns overprinted on hydrophilic tracks using layer–by–layer printing method: (a) optical microscopic image of 3-times printed PR pattern, (b) cross-sectional profile of 30 μm line width, (c) cross-section profile of 60 μm line width, (d) optical microscopic image of FC/PR pattern.

Figure 5. Results of AFM analysis on 1 μm × 1 μm scanned area before and after Al₂O₃ ALD on various surfaces: (a) bare Si; (b) Al₂O₃-deposited Si surface; (c) FC-coated Si (FC/Si) surface; (d) Al₂O₃-deposited FC/Si surface; (e) PR-coated Si (PR/Si) surface; (f) Al₂O₃-deposited PR/Si surface; (g) FC-covered PR/Si (FC/PR/Si) surface; (h) Al₂O₃-deposited FC/PR/Si surface.

Figure 6. Results of AFM and TOF-SIMS analyses of Al₂O₃ AS-ALD process using FC inhibition pattern: (a) AFM image of FC inhibition pattern on Si substrate; (b) AFM image of Al₂O₃ pattern formed by O₂ plasma lift-off process; (c) TOF-SIMS AlO^– signal of FC patterns on Si substrate, (d) TOF-SIMS CF- signal of FC patterns on Si substrate, (e) TOF-SIMS AlO^– signal after Al₂O₃ deposition, (f) TOF-SIMS depth intensity of AlO^– signal in the background and FC pattern regions.

Figure 7. Optical microscope images before and after ultrasonic agitation using acetone for Al₂O₃-deposited PR pattern: (a) Al₂O₃ deposited PR patterns; (b) Al₂O₃-deposited PR pattern after 15-min ultrasonic agitation.

Figure 8. Results of AFM and TOF-SIMS analyses of Al₂O₃ AS-ALD process using FC/PR inhibition pattern: (a) three-dimensional image and (b) cross-sectional profile of patterned Al₂O₃ measured by AFM; (c) TOF-SIMS AlO^– signal after lift-off process using 0.45 µm thick FC/PR pattern; (d) TOF-SIMS AlO^- signal and (e) Si^– signal after lift-off process using 1.28 µm thick FC/PR pattern; (f) TOF-SIMS depth intensity of AlO^– signal in the background and 1.28 µm thick FC/PR pattern regions.