ASM International (Netherlands)

The recently introduced Direct Bonded Heterogeneous Integration (DBHi) Si bridge technology has chips connected by a bridge housed inside a cavity or trench that is precisely machined in the chip-carrier laminate. The size, thickness, and placement centrality of the bridge are critical parameters that are necessary to prevent interference with the laminate substrate trench. In this study, we compared laser and saw dicing processes for the DBHi bridge technology. Different laser dicing recipes are developed and optimized. The laser and saw dicing process are compared for dimensional tolerances, edge quality, and die strength of the bridge chips. The die strength is affected by the edge defects on the top and bottom surfaces adjacent to the edges and is measured using a three-point bend fixture in a Universal Testing Machine (UTM). The laser dicing process is improved to equalize the die strength at both the surfaces as well as to achieve equal or higher die strength than blade dicing specifically for the thinner wafer thicknesses.

ABSTRACTUltrathin silicon nitride capacitors were fabricated using in-situ multiprocessing technology. In this paper we present comparative studies of capacitor formation using standard furnace processing, rapid thermal processing (RTP), and cluster tool processing of ONO dielectric films. We show that, due to better interface control using cluster tool processing, higher capacitance can be obtained for a fixed leakage level for the same thickness of dielectric film when compared to furnace and rapid thermal processing. We discuss the structural and electrical properties of these films and show that, due to an oxide-free interface, the improved film quality results in lower leakage current density and higher reliability.

In this paper the thermal behavior of a diffusion furnace is studied. The ultimate goal is to achieve control of the wafer temperatures. It is shown how some previous results from the literature on the behavior of wafer temperatures in a diffusion furnace are incomplete and partly erroneous. A control algorithm has been derived which achieves much better wafer-to-wafer uniformity than conventional control.

Silicon oxynitride films with varying oxygen/nitrogen ratio were grown from SiH4, N2O, and NH3 by means of a plasma-enchanced chemical vapor deposition process. The elemental composition of the deposited films was measured by a variety of high-energy ion beam techniques. To determine the chemical structure we used Fourier transform infrared absorption spectroscopy and electron-spin resonance. Ellipsometric data and values for mechanical stress are also reported. We show that the entire range of compositions from silicon oxide to silicon nitride can be covered by applying two different processes and by adjusting the N2O/NH3 gas flow ratio of the respective processes. It is suggested that the N2O/SiH4 gas flow ratio is the major deposition characterization parameter, which also controls the chemical structure as far as the hydrogen bonding configuration is concerned. We found that the films contain significant amounts of excess silicon and that the mechanical stress in the oxynitrides is lower than in plasma nitride. The electron-spin density is low (∼1017/cm3) in all samples.