Interconnections on Chips

A current example of a problem that can be simplified through segregation of its components by physical scale is the deposition of on-chip interconnects onto a wafer. Takahashi and Gross have analyzed the scaling properties of interconnect fabrication problems and identified the relevant control parameters for the different levels of pattern scale [135], They define several dimensionless groups which determine the type of problem that must be solved at each level. 

For electrically short interconnections with high resistance, such as on-chip interconnections, signal delays are dominated by the rise time degradation due to the charging of the receiver capacitance by the interconnection resistance (fllineCrec) (54, 55). On PWBs in which resistance is negligible, the... 

Ramarajan S, Li Y, Hariharaputhiran M, Babu SV, Her YS. The role of alumina particle density in chemical mechanical planarization of copper, tantalum, and tungsten disks and films. J CMP On-Chip Interconnect IMIC 2000 l(l) 28-38. 

P.C. Andriacacos, Copper on-chip interconnections. Electrochem. Soc. Interface 8, 32-37, 1999. 

The multiscale systems approach is directly applicable to problems in nanotechnology, molecular nanotechnology and molecular manufacturing. The key ideas have been illustrated with examples from two processes of importance to the semiconductor industry the electrodeposition of copper to form on-chip interconnects and junction formation in metal oxide semiconductor field effect transistors. 

Andricacos, P.C. (1999) Copper on-Chip Interconnections - A Breakthrough in Electrodeposition to Make Better Chips. 

Andricacos PC (1999) Copper on-chip interconnections a breakthrough in electrodeposition to make better chips. Electrochem Soc Interface 8 32-37... 

Edelstein DC et al (1995) VLSI on-chip interconnection performance simulations and measurements. IBM J Res Dev 39 383 02... 

On-chip interconnects present parasitic capacitance and resistance as loads to active circuits. Such parasitic loads had little impact on earlier ICs because the intrinsic gate delay dominated the total gate delay. 

For a lossy transmission fine due to parasitic resistance of on-chip interconnects, an exponential attenuating transfer function can be applied to the signal transfer at any point on the transmission line. The rate of the attenuation is proportional to the unit resistance of the interconnect. When operating frequency increases beyond a certain level, the on-chip transmission media exhibits the skin effect in which the time-varying currents concentrate near the skin of the conductor. Therefore, the unit resistance of the transmission media increases dramatically. 

The feature size of the MCM interconnect is about 10 times that of the on-chip interconnect, reducing the interconnect disabled by processing defects to almost nil. By guaranteeing that only good die are... 

Copper Electrochemical Technology The mauufacture of complex microstructures for on-chip interconnects requires multiple layers of metallization. Copper electrochemical technology was introduced by IBM in 1999 and is now used widely as a basic chip fabrication process. The process depends critically on the action of solution additives that influence growth patterns during electrodeposition. 

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