| At present,in large-scale integrated circuits,copper interconnection technology has been widely used due to its low resistivity,low cost,and strong resistance to electromigration.The diffusion barrier layer can effectively block the migration of copper atoms during the use of integrated circuits.However,in devices with a larger aspect ratio,the traditional inorganic diffusion barrier layer can not meet the size requirements of today's integrated circuit components due to its large thickness,therefore,self-assembled organic diffusion barriers have gradually entered the field of view of scientists and become a new research hotspot.In this paper,11-mercaptoundecanoic acid(MUA)diffusion barrier layer is prepared on the surface of SiO2/Si(100)by molecular self-assembly technology,and its barrier performance is evaluated.In order to further improve the barrier performance of the MUA diffusion barrier,this article uses para-aminobenzoic acid to modify it.And the structure,morphology and thermal stability of the modified MUA barrier layer are systematically studied.Through the analysis of XPS test results,it is found that the existence of O=C-O bond can confirm that both MUA and p-aminobenzoic acid successfully bond with SiO2/Si(100)substrate,The formation of O=C-N bond proves that MUA has reacted with p-aminobenzoic acid,and the chemical bond has been connected;SEM,AFM,water contact angle tester were used to analyze the surface morphology and hydrophobicity of the samples.The test results show that when the MUA concentration is 0.1mmol/L,the film quality of the sample surface is the best.The roughness can reach 0.245±0.010nm,the terminal functional group mercapto groups are arranged in the most orderly,and the contact angle value can reach 69.6°±2°.After modification,when the ratio of the activator N-hydroxysuccinimide(NHS)to1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride(EDC)content is 2,the surface of the assembled film is the most flat and smooth,RMS=0.313±0.010nm,and the contact angle is 68.6°±2°.Copper film was deposited on the surface of the self-assembled film prepared by magnetron sputtering technology to prepare Cu/barrier/SiO2/Si samples.The leakage current current density measured by the semiconductor analyzer shows that the leakage current of the modified sample is 5×10-7A/cm2 under the condition of annealing at 300?.The introduction of a benzene ring with high steric hindrance inhibits the diffusion of Cu atoms to a certain extent,so that the leakage current density of the modified sample is reduced by an order of magnitude compared with the unmodified sample,and the diffusion barrier effect is improved;The results of the four-point bending test indicated that due to the strong bonding force between-SH and copper,the interface toughness of the modified sample was improved by nearly 76.9%compared with the pure copper sample;The test results of XRD,SEM and FPP show that the pure copper sample will diffuse Cu atoms and bond with Si in the substrate to produce Cu3Si at 200?,causing the copper film to fail,the failure temperature of the Cu/MUA/SiO2/Si sample is 350?,and the failure temperature of the modified sample rises to400?.The thermal stability has been improved to a certain extent,which can further improve the reliability of the device. |
PDF Full Text Request