Reactive Ion Etching of Copper Films

Schwartz, G. C.; Schaible, Philipp

doi:10.1149/1.2120092

Cited by 76 publications

(17 citation statements)

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“…The NH 3 and Cl 2 gases were connected with two gas delivery lines and independently controlled gas fluxes impinged onto the Cu surface through two separate nozzles positioned equidistant above the sample. The NH 3 and Cl 2 gases were connected with two gas delivery lines and independently controlled gas fluxes impinged onto the Cu surface through two separate nozzles positioned equidistant above the sample.…”

Section: Methodsmentioning

confidence: 99%

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Gas assisted etching of copper with focused ion beams

Edinger

1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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With the implementation of copper instead of aluminum as the metallization layer in high performance integrated circuits, the use of gas assisted etching of copper for focused ion beam ͑FIB͒ based failure analysis and circuit rewiring becomes important. In the present study the effects of exposing a copper substrate with a mixture of chlorine (Cl 2 ) and anhydrous ammonia (NH 3 ) during ion bombardment have been investigated. The exposure of the copper surface to Cl 2 or to NH 3 /Cl 2 mixtures leads to the formation of a reaction layer. The thickness of this layer and its texture depends on the FIB parameters such as ion beam dwell time, Cl 2 pressure, and the NH 3 to Cl 2 flux ratio. In addition, the experiments indicate that the formation of the reaction layer is enhanced in areas that have been previously exposed ͑i.e., damaged͒ with the ion beam. The etch yield shows a strong dependence on the ion beam dwell time and the gas flux. For short dwell times and low NH 3 and Cl 2 flux a 12-fold increase over physical sputtering could be achieved. With increasing Cl 2 flux the etch rate decreased and the maximum in the etch yield shifted to longer dwell times, indicating a change in the rate limiting step of the ion induced reaction sequence.

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Section: Methodsmentioning

confidence: 99%

“…3 It was shown that, due to the involatility of the reaction product, a substrate temperature of 225°C was needed to achieve considerable etch rates. 3 It was shown that, due to the involatility of the reaction product, a substrate temperature of 225°C was needed to achieve considerable etch rates.…”

Section: Introductionmentioning

confidence: 99%

Gas assisted etching of copper with focused ion beams

Edinger

1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…[23][24][25][26] This is higher than the reticulation temperature of most commercially available organic photoresists. Although direct subtractive copper etch technologies do exist, process temperatures above 210°C are required.…”

Section: Introductionmentioning

confidence: 94%

Review of trench and via plasma etch issues for copper dual damascene in undoped and fluorine-doped silicate glass oxide

Keil

Helmer

Lassig

2003

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Back side exposure of variable size through silicon viasDual damascene dielectric etch technology is emerging as a key enabler for advanced integration schemes. Early implementations of copper dual damascene processes favored the trench-first approach. This approach has now been largely superseded by the via-first scheme for technology nodes below 250 nm. Several etch issues typically arise when implementing either of these approaches. The via-first approach can lead to either via veils or excessive faceting problems when the trench is etched. The traditional trench-first approach requires long via overetches and very high selectivity to the underlayer so that allowance can be made for vias that are misaligned or placed outside the trenches. Trench-first lithography employing organic resists often requires patterning over nonplanar surfaces, which can result in narrow process windows. Both the via-first and trench-first approaches increasingly require etching the trench without a stop layer. This places exacting demands on etch uniformity, etch front control, and sidewall profile angle control. Control of these issues is enhanced when the etch mechanisms responsible for driving them are understood. These and other issues as well as the current understanding of the relevant mechanisms are discussed for implementing copper dual damascene structures in plasma enhanced chemical vapor deposition undoped silicate glass or fluorinated silicate glass oxide films.

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“…Since Cu is also a preferred interconnection material for future semiconductor chips, reactive ion etching of Cu has been studied more extensively than that of NiFe. It has been found that Cu can be etched in chlorine-containing plasmas [30,31]. In such a plasma, the Cu etching rate essentially depends on the desorption rate of the reaction product CuCL Since the use of a high temperature favors the desorption from surface, a higher etching rate can be achieved at an elevated temperature.…”

Section: Reactive Ion Etchingmentioning

confidence: 99%