Substrate-Dependent Area-Selective Atomic Layer Deposition of Noble Metals from Metal β-Diketonate Precursors

Abstract

Area-selective ALD of Ir, Ru, and Rh with excellent substrate selectivity was achieved by using metal β-diketonates, i.e., Ir(acac) 3 , Ru(thd) 3 , and Rh(acac) 3 , as precursors with either O 2 or air as a coreactant. Native SiO 2 and Ru were identified as growth surfaces while low-k SiOC, native oxide terminated Cu and Co, Al 2 O 3 , ZrO 2 , and HfO 2 were identified as the nongrowth surfaces. UV (254 nm) irradiation in air was proven efficient to activate the low-k SiOC surface for the noble metal growth. UV exposure of 1 min was sufficient for the growth activation yet without causing any damage to the low-k material. Selective growth of the noble metals was successfully demonstrated on a UV-irradiated test chip that has micro-and nanometer-scale low-k SiOC/Cu patterns. At the optimal selective deposition temperatures, that is 225 °C for the Ir, 300 °C for the Ru, and 250 °C for the Rh, films with a thickness of at least 10 nm for Ir and ∼30 nm for Ru and Rh can be selectively deposited on the UV-activated low-k SiOC regions, while no growth occurs on Cu regions, as characterized by SEM, TEM, and EDS.

High‐Throughput Area‐Selective Spatial Atomic Layer Deposition of SiO2 with Interleaved Small Molecule Inhibitors and Integrated Back‐Etch Correction for Low Defectivity

“…Yet, the exercise of considering surface acidity has already proven itself practical for designing areaselective ALD processes. [26,43] Furthermore, it is worth noting that the insertion of etch-back correction steps can in principle allow for further tuning of the selectivity. Depending on the "dutycycle" during supercycle approach, i.e., depending on the ratio of etching to deposition cycles, one can potentially achieve selective deposition of SiO 2 on Ta 2 O 5 and ZrO 2 but not on ZnO and IGZO, or alternatively have selective deposition on SiO 2 , ZrO 2 , Ta 2 O 5 and not on IGZO, ZnO, and TiO 2 .…”

Selection Criteria for Small-Molecule Inhibitors in Area-Selective Atomic Layer Deposition: Fundamental Surface Chemistry Considerations

“…While SiO 2 has mostly acidic OH groups, ZnO or Al 2 O 3 have more basic character, compared to SiO 2 , which explains the selective growth of SiO 2 on SiO 2 and not on Al 2 O 3 or ZnO when using acetylacetone (Hacac) as SMI. 3,26,27 The relative acidity of metal oxides surfaces based on the Sanderson's electronegativity was employed by Mameli et al to rationalize the selective chemisorption of Hacac, as summarized in Figure 2. 3 To approach a more realistic description of surface reactivity, one must consider that each metal oxide has several types of hydroxyl groups and depending on the coordination and the proximity of other functional groups and the extent of hydrogen bonding, the hydroxyls of a single surface may have a range of different acidic/basic character and thus different reactivity.…”

“…The acidity of the SMIs, with respect to the basicity of surface hydroxyl groups, can be used as a rule of thumb to predict whether these types of SMIs will chemisorb on the surface. While SiO 2 has mostly acidic OH groups, ZnO or Al 2 O 3 have more basic character, compared to SiO 2 , which explains the selective growth of SiO 2 on SiO 2 and not on Al 2 O 3 or ZnO when using acetylacetone (Hacac) as SMI. ,, The relative acidity of metal oxides surfaces based on the Sanderson’s electronegativity was employed by Mameli et al to rationalize the selective chemisorption of Hacac, as summarized in Figure …”

Area-Selective Etching of Poly(methyl methacrylate) Films by Catalytic Decomposition

“…Therefore, ASD eliminates complicated lithography and etching steps. Area-selective growth can be inherent, i.e., certain deposition processes work only on specific surfaces. , ASD can also be achieved by either activating or inactivating selected surfaces, for example, by inhibiting the growth on selected areas with self-assembled monolayers. , …”

“…Area-selective growth can be inherent, i.e., certain deposition processes work only on specific surfaces. 8,9 ASD can also be achieved by either activating or inactivating selected surfaces, for example, by inhibiting the growth on selected areas with self-assembled monolayers. 10,11 Area-selective etching (ASE) of polymers, first reported by Zhang et al, 12 is a self-aligning patterning technique which is based on different catalytic properties of different surfaces (Figure 1).…”