Novel method to achieve area selec0ve ALD on copper metal vs. SiO 2 using vapor-phase deposited SAMS

Transcription

1 Novel method to achieve area selecve ALD on copper metal vs. SiO 2 using vapor-phase deposited SAMS Laurent Lecordier, Ultratech CNT, Waltham USA Silvia Armini, IMEC, Leuven Be ALD 216 Dublin, Ireland 7/26/216

2 BoMom-up approach Present day Stage 1 Stage 2 Stage 3 convenbonal lithography TOP DOWN Economic raonal to bomom-up Directed Self-assembly TOP DOWN Future nanotech TOP DOWN Target $$$$ BOTTOM UP $ Paradigm shi< to Smart Materials BOTTOM UP Up to ?? Source: R. Dammel, Semicon Korean 215 Selecve area deposion Selecve deposion schemes Source: T. Younkin (Intel), SPIE-215, [9425-2], San Jose, CA, USA, Selecvely deposited capping layer BoMom-up trench fill Source: J. Engstrom, Cornell Univ. Selecve side wall deposion 2

3 SAMS as a barrier layer SAMS anatomy Functionalization Order Assembly Substrate Tail End group Head Group Single organic monolayer from ordered molecular 2D assembly formed spontaneously by the chemisorpon of the head group Defect-free densely packed SAMS Silane on oxide Goal use thiol SAM to enable at least 1 nm of HfN x ALD on SiO 2 while blocking deposion on copper >1 nm HfN Thiol x ALD on metals SiO 2 Cu HfN x ALD SiO 2 Source: C. Nicosia, DOI: 1.139/C3MH46J 3

4 What makes a good SAMS barrier Source: Silvia Armini, IMEC ` n < 12 n = 12 to 16 Increasing chain length n > 16 Increasing resistance to transport Ref: Jiang, X. & Bent, J Phys Chem C 113, (29). Prior works Good metal oxide and Pt ALD selecvity on oxides using silane SAMS deposited in li. phase or MCP LiMle has been done on metals substrates [1] Almost none has been done in vapor phase [2] 1. Hashemi, F. S.. ACS Nano (215) 2. Farm, E.. Selecve-Area Atomic Layer Deposion, Univ. of Helsinki Dissertaon 211. Vapor phase SAMS are scalable for manufacturing work well in 3D allow rapid processing Compable for ALD / SAMS codeposon 4

5 Hardware setup Use same 2-mm Savannah* for thiol SAMS and HfN x ALD Deposions at 17 C HfN x - TDMAHf and NH 3 thermal ALD C18 Thiol SAMS precursor (ODT) 1- Octadecanethiol CH 3 (CH 2 ) 17 SH Vapor C ~1 Torr But evaporaon rate x1 slower than C1-C12 SAMS High temp. pressure endpoint delivery SAMS kit L No glove box configuraon JJ Insitu thickness monitoring via Woollam M2 ellipsometer Insitu SE is crical to monitor both the SAMS growth and HfN x inhibion in real-me * IMEC: 3-mm glovebox Savannah 5

6 HfN x ALD on SiO 2 exposed to C18 thiol 1 HfN x ALD 8 Insitu thickness [Å] SiO 2 On SiO 2 (exposed to C18) HfN x ALD Cycle C18 thiol doesn t bound to SiO 2 HfN x shows 5-1cycle growth inhibion 6

7 HfN x ALD on copper with nave oxide 1 HfN x ALD 8 Insitu thickness [Å] CuO x - Cu On SiO 2 (exposed to C18) On Copper with Nave Ox HfN x ALD Cycle HfN x chemistries react on as-is copper leading to likely reducon of CuO x 7

8 HfN x ALD on reduced copper exposed to C18 thiol 1 HfN x ALD 8 Insitu thickness [Å] Reduced Cu On SiO 2 (exposed to C18) On Copper with Nave Ox. On reduced copper with C HfN x ALD Cycle HfN x on reduced Cu + C18 SAMS is inhibited for > 5 cycles >1nm ALD selecvity is achieved 8

9 HfN x ALD on reduced copper exposed to C18 thiol 1 HfN x ALD On SiO 2 (exposed to C18) 8 On Copper with Nave Ox. Insitu thickness [Å] Reduced Cu On reduced copper with C HfN x ALD Cycle Retardaon extends to >15 ALD cycles Underlying reacon during first 15 cycles 9

10 In-situ reducon of nave copper oxide Insitu SE thickness change during.1 s metalorganic 17 C on Cu/CuO x Insitu SE thickness [Å] CuO Cu 15 # of pulses TMA TDMAZr TDMAHf 2 25 Proposed reducon pathway 2Cu O + Al(CH 3 ) 3 CuAlO 2 + 3Cu + 2CH 4 +CH ads. Gharachorlou, A. et al. Acs Appl Mater Inter 7, (215). Cu + nat.ox WCA 92 Cu a{er insitu TDMAHf WCA 31 Cu a{er exsitu HCl wet clean WCA 32 Above 15 C, metal organic pulses (TMA, TDMAZr, TDMAHf) leads to paral reducon of copper nave oxide conducive to thiol reacon on reduced Cu 1

11 Insitu SE during undecanethiol deposions 15 Insitu SE thickness [Å] 1 5 UDT on SiO2 UDT on SiO2 UDT on HCl cleaned UDT on copper SiO2- x1 9s expo UDT on HCl cleaned copper x1 9s expo UDT on HCl cleaned copper - x3 3s expo < WCA Time [s] Use C11 Undecanethiol Too short for efficient blocking acon (2-3 cycles) but enables rapid characterizaon of SAMS growth behavior due to x1 refill rate No C11 growth observed on SiO 2 Self-limited C11 growth within 1 min. on reduced copper 11

12 Summary Cu+ CuO x Al y TMA octadecanethiol Nat. ox. CuO x SiO2 Cu SiO2 Cu SiO2 Cu Hf3N4 SiO2 Cu Si Si Si Si a. b. c. d. Copper oxide is reduced in-situ above 15 C using TMA/ TDMAHf or TDMAZr A dense self-limited ODT SAMS is selecvely deposited in <15 min in vapor phase on reduced copper vs. SiO 2 The SAMS layer acts as an efficient barrier blocking HfN x ALD for >15 cycles Selecve ALD deposion of more than 1nm HfN x on SiO 2 vs copper is demonstrated All the steps were performed in-situ in a single tool ODT delivery is challenging and will reuire improved delivery systems Process integraon in a glove box will be beneficial (IMEC pla~orm) due to rapid oxidaon kinecs of copper Patent applica8on # 62/244,467 Methods of forming an ALD-inhibi8ng layer using a selfassembled monolayer 12