Bok Heon Kim

Development and Characterization of a PECVD Silicon Nitride for Damascene Applications

A silicon nitride film, Damascene Nitride™, is deposited in a plasma-enhanced chemical vapor deposition (PECVD) chamber with a conical hole faceplate using silane and ammonia as precursors. Fourier transform infrared analysis indicates that Damascene Nitride is similar to a high-density plasma nitride film. Hydrogen forward scattering spectroscopic analysis shows the films hydrogen content to be 13%, ~6% less than other PECVD nitride films, leading to a 20% improvement in etch selectivity to fluorinated silicate glass. Secondary ion mass spectrometric analysis shows that Cu diffusion is <250 A in the nitride; a low leakage current is confirmed through bias temperature stress testing. The higher density of Damascene Nitride leads to higher etch selectivity and better Cu barrier properties, allowing a thinner nitride film to be used. Thinner nitride layers, in addition to the lower dielectric constant (κ) of Damascene Nitride, leads to a 5-6% reduction in resistance-capacitance delay when Damascene Nitride is used with low-κ dielectric materials.

Defect gallery and bump defect reduction in the self Aligned Double Patterning module

The Self Aligned Double Patterning (SADP) module is one scheme to form 3X or 2X line structures by using a dry scanner or immersion scanner. After reliable processes are developed, defect data collection, understanding, characterization, and reduction become important. The learning we obtained at the Mayden Technology Center at Applied Materials reduced ramp time at our customer sites and provided new directions to improve our processes. In this paper, the defect type and evaluation per process to the final 3X or 2X structures in SADP flow are discussed. An in-depth study of the impact of bump defects, bump formation, and a potential solution involving an improved film deposition process are presented.

Benchmarking Four Point Bend Adhesion Testing: The Effect of Test Parameters On Adhesion Energy

The four‐point bend test method has been widely used to quantify the adhesion energy of interfaces in multilayer thin film stacks. However, the adhesion energy of an interface (Gc) may be effected by variances in the specimen preparation method and test procedure. In the present study, a less time consuming method of specimen preparation that involved cleaving (DPN‐free method) rather than dicing of specimen was found to offer a 90% test success rate with high accuracy and repeatability. The epoxy curing temperature and time were minor factors affecting Gc and their effect was within the test standard deviation of 0.3 J/m2. For a higher Gc interface, the epoxy thickness was found to result in a 20% increase in measured Gc as the bond layer was increased from 7 to 50 μm. The measured value of Gc also increased by 20% as the displacement rate was increased from 0.05 μm/s to 0.5 μm/s. The notch or scribe used to initiate the crack was found in one stack structure to have an effect on the interface that debonded. The delamination interface can be modulated through control of the notching step during sample preparation.

Reliability of dielectric barriers in copper damascene applications

The film properties of two PECVD deposited dielectric copper barrier films have been optimized to improve BEOL device reliability in terms of electromigration. Two critical aspects that affect electromigration are the dielectric barrier film hermeticity and adhesion to copper. We use a method to quantify the barrier film hermeticity of the BLO/spl kappa/ I low-/spl kappa/ dielectric film to be similar to that of silicon nitride. In addition, the interfaces between damascene nitride with copper, as well as BLO/spl kappa/ I with copper have been engineered to improve the interfacial adhesion energy to >10 J/m/sup 2/ for both damascene nitride and BLO/spl kappa/ I.

Reliability of Dielectric Barrier Films in Copper Damascene Applications

The film properties of two PECVD deposited dielectric copper barrier films have been optimized to improve BEOL device reliability in terms of electromigration. Two critical aspects that affect electromigration are the dielectric barrier film hermeticity and adhesion to copper. We use a method to quantify the barrier film hermeticity and have optimized the hermeticity of the BLOκ™ low-κ dielectric barrier film to be similar to that of silicon nitride. By using FT-IR we find that the film porosity has a much stronger effect than the film stoichiometry on hermeticity. In addition, the interfaces between Damascene Nitride™ with copper, as well as BLOκ with copper have been engineered to improve the interfacial adhesion energy to >10 J/m2 for both Damascene Nitride and BLOκ.

PECVD Silicon Nitride for Damascene Applications

A Pecvd silicon nitride film, Damascene Nitride™, is deposited in a PECVD chamber with a hollow cathode faceplate using silane and ammonia as precursor gases. Various techniques (FTIR, RBS-HFS, SIMS, TDS and BTS) were used to characterize the structure, composition, density and wet etch rate of the film. FTIR analysis indicates that Damascene Nitride is very similar to a high density plasma (HDP) nitride film. HFS analysis shows the films hydrogen content to be 13%,∼6% less than other PECVD nitride films, leading to a 20% improvement in etch selectivity to FSG. The film wet etch rate is 2 times slower than that of other PECVD nitrides, and the dielectric constant k was measured to be 6.8, which is lower compared to other PECVD nitrides and HDP CVD nitrides where k∼ 7.0 and 7.5, respectively. SIMS analysis shows that Cu diffusion is