Molybdenum Taper Dry Etching

Hosoya, Tetsuo; Ohfuji, Shin‐ichi; Shibata, Toshitaka

doi:10.1149/1.2115766

Cited by 9 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is known that plasma containing Cl 2 and Cl etches metallic molybdenum fast (≈ 20 nm/min), especially in elevated temperatures [25]. A small addition of oxygen (by using CCl 4 /O 2 mixtures) makes this process several times faster [26]. CCl 4 and CHCl 3 were also chosen due to the fact that they are not as chemically aggressive to metal parts of the dosing valve as gaseous Cl 2 .…”

Section: Methodsmentioning

confidence: 99%

Production of Mo⁺Beams Using an Arc Discharge Ion Source

et al. 2014

View full text Add to dashboard Cite

A new method of Mo+ ion beam production is presented in the paper. The method bases on the chemical sputtering/etching of the molybdenum parts (e.g. anode) of the arc discharge ion source by the chloride containing plasma. A mixture of CCl4 (or CHCl3) vapor and air was used as the feeding substance. The separated Mo + beam current of approximately 18 µA was achieved. The measurements of the ion current dependences on the discharge and lament currents as well as on the magnetic eld ux density from the electromagnet surrounding the discharge chamber were performed in order to nd the optimal working parameters of the ion source.

show abstract

Section: Methodsmentioning

confidence: 99%

Production of Mo⁺Beams Using an Arc Discharge Ion Source

et al. 2014

View full text Add to dashboard Cite

show abstract

“…It is i m p o r t a n t , therefore, t h a t t h e amount of oxygen from residual air, dissociated water vapor, or gases entrapped in the target materials be as low as possible in the deposition system. The amount of oxygen in Mo films was also shown to affect plasma etch rates (26,27,63). Figure 13 shows the difference in etch rates of Mo films from two different sources using a 25% CC14/75% 02 plasma.…”

Section: Methodsmentioning

confidence: 99%

“…It is believed that this additional in situ oxygen enhances the etch rate because it aids in the formation of the volatile molybdenum oxychlorides. Tapered dry etching techniques have been developed based on faster and isotropic etching of Mo films heavily doped with oxygen (63). This characteristic has been used to improve step coverage of subsequent layers by producing a tapered Mo sidewall.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Reactive Ion Etching of Molybdenum and Bilayer Metallization Systems Containing Molybdenum

Saia

Gorowitz

1988

J. Electrochem. Soc.

View full text Add to dashboard Cite

Refractory metals such as molybdenum (Mo) are seeing increased usage in VLSI circuit designs, primarily due to their thermal stability. Properties desirable for a VLSI metallization system with contact to silicon include high metal conductivity, good thermal stability, absence of spiking, minimal electromigration, corrosion resistance, good adhesion, and low contact resistance. It is very difficult to fulfill all of these requirements with just a single molybdenum layer. Other metals such as Cr, Ti, A1, or TiW can be used as thin underlayers to obtain the properties desired. We will describe processes for the reactive ion etching of Mo, and recent work in which chloro/fluoro gas mixtures such as CC12F2/O2, SF6/C12, and SF6/C12/ 02 have been used to etch bilayer metallization systems containing Mo, particularly Mo/TiW. In this study, the effects of different cathode cover plate materials, plasma chemistries, and other processing parameters on the etch rate, selectivities, and sidewall profiles were investigated. An analysis of plasma etch chemistry, using the results of emission spectroscopy, is presented. The methods used for the metal deposition and processing of Mo are also shown to be key factors in determining etching characteristics.Refractory metals and metal silicides have emerged as important candidates for use in the fabrication of VLSI circuits (1-7). As early as 1971, Brown et al. (8-10) described the use of Mo for fabricating self-aligned, high-speed MOSFET's. Polysilicon has a number of properties that make it useful for gate or interconnect applications, but when compared to refractory metals (Mo, W) (11), its high resistivity can limit the performance of gate-level interconnections, especially as it affects the speed of smallgeometry, densely packed circuits (12-13). Molybdenum or tungsten, on the other hand, have resistivities up to two orders of magnitude lower than that of heavily doped polysilicon.In multilevel metal structures (14, 15), the choice of materials used for the lower levels of interconnections depends not only on electrical and metallurgical requirements, but also on the ability of the metal to withstand the high temperatures that it might be subjected to in subsequent processing steps. Aluminum or aluminum alloys, traditionally used interconnect materials, have relatively poor high-temperature capabilities. They react with silicon at only a few hundred degrees (16) and can form a eutectic with Si at temperatures above 550~ that can cause complete circuit failure (17, 18). Therefore barrier layers, such as platinum silicide or titanium-tungsten alloys, must be used to limit such reactions. Furthermore, aluminum alloys preclude the use of processing temperatures above 450~ after their deposition. The long-term stability of finished devices may also be affected because of electromigration.Molybdenum, which has a melting point of 2610~ and reacts with silicon at much higher temperatures than aluminum, can remain stable during subsequent anneals, diffusions, and depositions. It can be ...

show abstract

“…However, it generally involves a high process cost, and is very hard to be applied to a large-scaled flat panel displays. Instead, various tapered etching techniques which can control a taper angle of thin film patterns have been developed so far as an alternative method to CMP such as bilayer [3][4][5][6][7], etching temperature variation [8,9], grain size variation [10,11], etc. However, bilayer method requires etchselective materials having different etch rate for the same etchant in order to form a gradual taper profile, which limits the selection of materials.…”

Section: Introductionmentioning

confidence: 99%