Via Cleaning Technology for Post Etch Residues

Abstract:

Interconnect RC delay is the limiting factor for device performance in submicron semiconductor technology. Copper and low-k dielectric materials can reduce this delay and have gained widespread acceptance in the semiconductor industry. The presence of copper interconnects provides unprecedented challenges for via cleaning technology and requires the development of novel process chemistries for improved device capability.

• Periodical: Solid State Phenomena (Volumes 103-104)
• Pages: 357-360
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.103-104.357
• Online since: April 2005
• Authors: B.G. Sharma, Chris Prindle
• Keywords: Acid, Etch Residues, Polymer, Solvent, VIA, Via Chain Yields, Yield

References

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[5] D. Louis, et. al., IITC Proc., 289, 2001. Table 1: Relative wet clean performance of acid and solvents Process Chemistry Base Fluid Type Residue Removal Efficiency Contact Resistance Via Chain Yield Dilute Acid A Inorganic acid Good Low Very Good Dilute Acid B Inorganic acid mix Good Low Very Good Dilute Acid C Organic acid mix Good, CD loss Low Good Solvent A Fluoride Good Low Good Solvent B Fluoride Good Low Good Solvent C Amine Good Low Good Solvent D Organic acid Poor Low Good DI water Polar Poor High Low No clean None None High Low Fig. 1: No wet cleans Fig. 2: Acid A wet cleans Fig. 3: Acid B wet cleans Fig. 4: Solvent A wet cleans Fig. 5: Solvent B wet cleans Fig. 6: Solvent C wet cleans %Cum Solvent B Acid A Solvent A No Clean No Clean Solvent C Acid A Solvent B Solvent A Rcont: Contact Resistance Rcont: Contact Resistance Fig. 7: Contact resistance for different cleans Fig. 8: Via chain yield and contact resistance 200 400 600 800 1000 1200 1400 1600 1800 2000 0 1 2 3 4 5 6 7 8 9 10 Via Cleaved Si Si C O N File: hm016941 without clean Scale: 141.475 kc/s Offset: -581.419 kc/s Ep: 20.00 kV Ip: 4.826e-09A Kinetic Energy (eV) N(E)*E,ndiff9 F AES Survey PC 6 Sep 01 Area: 2 Acq Time: 16.01 min No Clean No Clean Acid Clean Acid Clean Fig. 9: TOF-SIMS analysis shows a reduction of Fig. 10: Auger analysis shows the presence of C, O, about 75% in CF compounds with acid wet cleans F, Si, and hints at the presence of N and F in via sidewall and cleaved dielectric. Multiplexed data showed significant concentration of C.