Atomic layer deposition of barriers for interconnect

Besling, W.; Satta, Alessandra; Schuhmacher, Jörg; Abell, Thomas; Sutcliffe, Victor; Hoyas, Ana Martin; Beyer, Gerald; Gravesteijn, D.J.; Maex, Karen

doi:10.1109/iitc.2002.1014959

Cited by 11 publications

(19 citation statements)

References 7 publications

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“…(138,139) For Cu interconnects, the incompatibility of chloride chemistry on Cu was suggested as a potential problem for halogen-based TiN ALD. (105,140) Considerable pitting has been observed during TiN ALD on Cu, which was attributed to the formation of a volatile CuCl product or reduction of Cu oxide by chloride. This was less significant at low growth temperature below 300 °C.…”

Section: Ald Tin: Diffusion Barrier Properties and Other Device Relatmentioning

confidence: 99%

Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing

Kim

2003

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

545

388

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Atomic layer deposition (ALD) has been studied for several decades now, but the interest in ALD of thin metal/nitrides films has increased only recently. This is driven by the need for highly conformal nano-scale thin films in modern semiconductor device manufacturing technology. ALD is a very promising deposition technique with the ability to produce thin films with excellent conformality and compositional control with atomic scale dimensions. However, the application of ALD to metals and nitrides in real semiconductor device processes requires a deeper understanding about the underlying deposition process as well as the physical and electrical properties of the deposited films. This paper reviews the current research efforts in ALD for metal and nitride films as well as their applications in modern semiconductor device fabrication.

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Section: Ald Tin: Diffusion Barrier Properties and Other Device Relatmentioning

confidence: 99%

Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing

Kim

2003

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

545

388

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“…Cu II (tmhd) 2 and H 2 penetrate the MSQ, and that H 2 is needed to reduce the copper precursor inside the MSQ. The volatile precursor probably leaves the MSQ during cool-down after the deposition with pure Ar.…”

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confidence: 99%

“…Figure 1 shows the RBS-determined areal density of copper deposited on SiO 2 and MSQ. These results are expressed as equivalent thickness, i.e., the thickness of metallic copper with the measured number of copper atoms per cm 2 . Experiments were carried out over deposition times ranging from 20 min to 90 min.…”

mentioning

confidence: 99%

“…Most solid materials with processing compatibility have a dielectric constant greater than two. Since the dielectric constant for air is one, reducing the dielectric constant can be achieved by making a film porous.[1] Recently, several authors have shown (either theoretically or experimentally) that porosity can have an adverse effect on the process of depositing films by CVD, [2,3] i.e., the gaseous precursors used in the deposition process penetrate into the film rather than being deposited onto the surface.In this paper, we show that copper CVD via Cu II (tmhd) 2 and H 2 on an organosilicate, nanoporous methyl silsesquioxane (MSQ), results in penetration and accumulation of copper at the interface between the dielectric layer and the substrate. This result is demonstrated by both Rutherford backscattering (RBS) spectrometry and scanning electron microscopy (SEM).…”

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confidence: 99%

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Copper Penetration into Porous Ultra‐low‐κ Methyl Silsesquioxane during Selective CVD

Jezewski¹,

Lanford

Senkevich

et al. 2003

Chemical Vapor Deposition

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Recently there has been intense interest in porous materials. For example, the performance of gigascale integrated devices may be improved by reducing resistive/capacitive (RC) delays with the introduction of ultra-low-k dielectrics (k < 2.0). Most solid materials with processing compatibility have a dielectric constant greater than two. Since the dielectric constant for air is one, reducing the dielectric constant can be achieved by making a film porous.[1] Recently, several authors have shown (either theoretically or experimentally) that porosity can have an adverse effect on the process of depositing films by CVD, [2,3] i.e., the gaseous precursors used in the deposition process penetrate into the film rather than being deposited onto the surface.In this paper, we show that copper CVD via Cu II (tmhd) 2 and H 2 on an organosilicate, nanoporous methyl silsesquioxane (MSQ), results in penetration and accumulation of copper at the interface between the dielectric layer and the substrate. This result is demonstrated by both Rutherford backscattering (RBS) spectrometry and scanning electron microscopy (SEM).That any deposition took place at all was unexpected since the literature indicates that CVD below the decomposition temperature of the precursor, with copper(II) b-diketonates, occurs only on metallic substrates.[4±7] The reasons suggested for this selectivity include both the lack of electron transfer, and thus proper dissociation of the precursors on insulating substrates, [6] and the absence of chemisorption sites. [8] Insulating dielectrics lack the prerequisite surface chemistry for proper dissociative adsorption of both the precursor and molecular hydrogen needed in CVD. This argument should hold for porous MSQ. Here, we show that deposition proceeds on MSQ at temperatures well below thermal decomposition, but only in the presence of hydrogen. As a control, bare SiO 2 substrates were placed in the deposition chamber, and no deposition occurred. The fact that this precursor has thermal stability is supported by the work of Martenson and Carlsson, [9] and Turgamaeva et al. [10,11] These authors present data that supports the assertion of thermal stability up to 260 C for Cu II (tmhd) on oxide/metal surfaces. The deposition temperature used here was 217 C. Depositions were made for several different time periods. Figure 1 shows the RBS-determined areal density of copper deposited on SiO 2 and MSQ. These results are expressed as equivalent thickness, i.e., the thickness of metallic copper with the measured number of copper atoms per cm 2 . Experiments were carried out over deposition times ranging from 20 min to 90 min. There was essentially no copper deposition on the SiO 2 substrate, whereas monotonic growth proceeded after 20 min on the MSQ dielectric. A 60 min copper CVD was carried out using just Ar (no H 2 ). The growth on SiO 2 and MSQ was 0.04 nm and 0.2 nm, respectively. This is to be compared with the growth of 43 nm of copper in MSQ during the same time period, but with H 2 . These data suggest tha...

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“…As a result, the ULK dielectric cannot be metallized by advanced deposition processes, such as atomic layer deposition (ALD) or CVD, since the metal±organic precursors will be deposited throughout the dielectric instead of just at its surface. [3,4] In order to seal the ULK dielectric so that it may be metallized, we have used a thermal CVD polymer, poly(p-xylylene) or parylene-N, and have coined the term Molecular Caulk to describe the process and materials that utilize the parylene platform. [5] A prime consideration of any pore sealing process for dual damascene architecture is the necessity of not having deposition on the Cu via.…”

mentioning

confidence: 99%

Selective Deposition of Ultrathin Poly(p‐xylene) Films on Dielectrics Versus Copper Surfaces

Senkevich¹,

Wiegand²,

Yang³

et al. 2004

Chemical Vapor Deposition

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Ultrathin films of poly(p‐xylylene) are selectively deposited on oxide surfaces but not on air exposed copper. The polymers are deposited under conditions favorable for forming highly conformal ultrathin films appropriate for ‘pore sealing’ the surface of ultra‐low κ dielectrics. Variable angle spectroscopic ellipsometry is used to measure the polymer deposit on SiO2, and shows the lack of deposition on air‐exposed copper. X‐ray photoelectron spectroscopic analysis of the copper samples shows deposition of adventitious carbon on the metal surface, and confirms that no polymer deposition occurs.

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Atomic layer deposition of barriers for interconnect

Cited by 11 publications

References 7 publications

Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing

Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing

Copper Penetration into Porous Ultra‐low‐κ Methyl Silsesquioxane during Selective CVD

Selective Deposition of Ultrathin Poly(p‐xylene) Films on Dielectrics Versus Copper Surfaces

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