Effects of Seeding Layers on Electroless Copper Deposition

1999 ◽  
Vol 564 ◽  
Author(s):  
Kai Yu Liu ◽  
Man Siu Tse ◽  
Wang Ling Goh
Keyword(s):  
Crystal Orientation ◽  
Copper Deposition ◽  
Complexing Agent ◽  
Copper Films ◽  
X Ray Diffraction ◽  
Seeding Layer ◽  
Initial Nucleation ◽  
Electroless Copper ◽  
Key Factor ◽  
Al Metallization

AbstractCopper has been actively pursued as the most promising candidate for replacing the current Al metallization for ULSI interconnection because of its higher electrical conductivity and resistance to electromigration. In this work, we present our experimental results on electroless copper deposition on various seeding layers from a formaldehyde-based solution with EDTA as a complexing agent. For electroless plating, a seeding layer is essential for the initiation of copper deposition. X-ray diffraction analysis revealed a variation in the crystallographic orientation of the electroless deposited copper with different underlying seeding layers. The seeding layer is the key factor affecting copper nucleation and grain growth. The initial nucleation behaviors of electroless copper deposition on palladium and copper seeding layers were investigated. The microstructure of electroless deposited copper blanket films was studied using both SEM and AFM, and the crystallinity was analyzed using XRD. The crystal orientation and surface texture of the electroless deposited copper films could be modified by thermal annealing in vacuum (10E-6 Torr) for 30 min at temperatures ranging from 200°C to 300°C. The ratio of crystal orientation, I(111)/I(200) increased with higher annealing temperature, indicating enhanced growth of the (111) crystal structure.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

Stress and Strain Evolution in Electroless Copper Films Evaluated with X-ray Diffraction and Substrate Curvature

2013 ◽  
Vol 160 (6) ◽  
pp. D226-D232 ◽  
Author(s):  
Tanu Sharma ◽  
Ralf Brüning ◽  
Colby Brown ◽  
Allison Sibley ◽  
Johannes Etzkorn ◽  
...  
Keyword(s):  
Stress And Strain ◽  
Copper Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strain Evolution ◽  
Electroless Copper ◽  
Substrate Curvature

Strain in electroless copper films monitored by X-ray diffraction during and after deposition and its dependence on bath chemistry

2011 ◽  
Vol 519 (13) ◽  
pp. 4377-4383 ◽  
Author(s):  
Ralf Brüning ◽  
Bruce Muir ◽  
Eric McCalla ◽  
Émilie Lempereur ◽  
Frank Brüning ◽  
...  
Keyword(s):  
Copper Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electroless Copper

Combining X-Ray Diffraction and Substrate Deflection Analysis to Understand Internal Stress in Electroless Copper Films

2012 ◽  
Vol 1529 ◽  
Author(s):  
Tanu Sharma ◽  
Ralf Brüning ◽  
Delilah A. Brown ◽  
Simon Bamberg ◽  
Michael Merschky ◽  
...  
Keyword(s):  
Internal Stress ◽  
Printed Circuit Boards ◽  
Film Surface ◽  
Local Stress ◽  
Conducting Layer ◽  
Copper Films ◽  
X Ray Diffraction ◽  
Plating Bath ◽  
X Ray ◽  
Electroless Copper

ABSTRACTElectroless copper films are usually the first conducting layer on the insulating substrates of printed circuit boards. For this and other emerging applications, the internal stress of the copper layer is an important consideration both for film adhesion and film-substrate interaction. We have combined stress/strain analysis based on X-ray diffraction, which is sensitive to the strain of the copper crystallites, with a conventionally used technique that analyses the bending of the substrate (Deposit Stress Analyzer). Both techniques were implemented in such a way that the stress could be monitored continuously during the deposition of the films from the electroless plating bath as well as afterwards. These tests were carried out for three chemical formulations and the results from both techniques agree qualitatively. For one bath, the substrate bending method detects a 60 nm region of local stress at the film-surface interface.

Organic Solution Deposition of Copper Seed Layers onto Barrier Metals

2000 ◽  
Vol 612 ◽  
Author(s):  
H. Gu ◽  
R. Fang ◽  
T. J. O'Keefe ◽  
M. J. O'Keefe ◽  
W.-S. Shih ◽  
...  
Keyword(s):  
Thin Films ◽  
Seed Layer ◽  
Copper Deposition ◽  
Copper Films ◽  
Exchange Reactions ◽  
Organic Solution ◽  
Spontaneous Deposition ◽  
Electroless Copper ◽  
Barrier Metal ◽  
Seed Layers

AbstractSpontaneous deposition of copper seed layers from metal bearing organic based solutions onto sputter deposited titanium, titanium nitride, and tantalum diffusion barrier thin films has been demonstrated. Based on electrochemically driven cementation exchange reactions, the process was used to produce adherent, selectively deposited copper metal particulate films on blanket and patterned barrier metal thin films on silicon substrates. The organic solution deposited copper films were capable of acting as seed layers for subsequent electrolytic and electroless copper deposition processes using standard plating baths. Electroless and electrolytic copper films from 0.1µm to 1.0µm thick were produced on a variety of samples on which the organic solution copper acted as the initial catalytic seed layer. The feasibility of using organic solution deposited palladium as a seed layer followed by electroless copper deposition has also been demonstrated. In addition, experiments conducted on patterned barrier metal samples with exposed areas of dielectric such as polyimide indicated that no organic solution copper or palladium deposition occurred on the insulating materials.

scholarly journals Analysis of stress/strain in Electroless Copper Films

2013 ◽  
Vol 2013 (1) ◽  
pp. 000026-000030 ◽  
Author(s):  
Tobias Bernhard ◽  
Simon Bamberg ◽  
Frank Brüning ◽  
Ralf Brüning ◽  
Laurence J. Gregoriades ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Copper Film ◽  
Theoretical Concept ◽  
Composition Gradient ◽  
Stress Profile ◽  
Copper Films ◽  
X Ray Diffraction ◽  
Polymer Substrates ◽  
Electroless Copper ◽  
Strain Stress

Polymer substrates were chemically coated with copper using various electroless copper baths and the internal strain/stress, as well as the adhesion quality, in the resulting copper films were studied during and after deposition as a function of the deposit thickness and the operation parameters of the electroless bath. The appearance of internal compressive stress in the copper film correlates to the probability of buckle driven delamination failure (blistering). Based on a simple theoretical concept we derived limits of allowed compressive stress in the copper film without inducing this failure mode. Furthermore depth-resolved X-ray diffraction (XRD) measurements in up to 1 μm thick electroless films indicate an approximately linear internal stress profile from about +200 MPa tensile stress at the substrate/adsorbate interface to −100 MPa compressive stress at the surface of the deposit. This will be explained in terms of a possible composition gradient of nickel in the copper film.

Strain in Electroless Copper Films: Analysis by in situ X-Ray Diffraction and Curvature Methods

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 001358-001388
Author(s):  
Simon Bamberg ◽  
Tobias Bernhard (corresponding author) ◽  
Laurence J. Gregoriades (presenting author) ◽  
Frank Brüning ◽  
Ralf Brüning ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Copper Film ◽  
Film Stress ◽  
Copper Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Electroless Copper ◽  
The Difference

Strain in chemically deposited copper films on polymer substrates was determined by means of in situ X-ray diffraction (XRD), deposit stress analyzer (DSA) and spiral contractometer (SC). The strain evolution of the films was studied as a function of copper film thickness and electroless copper bath parameters, during and after deposition. The results are not indicative of a preferred crystallite orientation or texturing in the deposit. The copper film stress is controllable over a wide range of some 100 MPa from compressive to tensile stress by appropriate variation of bath parameters (e.g. temperature, concentration of bath components such as nickel, stabilizer and formaldehyde). A higher tendency of blister generation for relaxed or compressively stressed films is apparent, which implies that a sufficient level of tensile stress throughout the deposition promotes film adhesion. An observable change from tensile to compressive film stress during the cooling of the sample from bath operation to rinse water temperature is discussed in terms of substrate-induced thermal stress to the copper film. In this context, the difference in the substrate materials required for XRD (polymer), DSA (copper) and SC (stainless steel) may be a significant factor contributing to the diverging measured stress behaviors of the methods. Moreover, it is questionable whether SC stress data can be compared with XRD and DSA stress data, due to the low resolution of the SC method (~60 MPa).

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