Recent Publications
The intention of publications made by Atotech is to share the results of our extensive research and development on a non commercial basis. With these presentations we aim to provide in-depth process information and inform about the latest investigations and results in each technology field. It should enable the reader to gain a complete and comprehensive understanding of our process solution and of general phenomena encountered in the electroplating industry.
This segment presents the recent papers from the business technology team circuitization & metallization of dielectrics (CMD).
P-66: Wet Chemical Metallization for High-End Flat Panel Display Manufacturing
Simon Bamberg, Birgit Beck, Horst Brüggmann, Frank Brüning, Elisa Langhammer, Christian Lowinski, Michael Merschky, Jörg Schulze, Johannes Etzkorn, Atotech Deutschland GmbH, Erasmusstraße 20, 10553 Berlin, Germany, May 2011
Recently the use of Copper as a conductor material for Thin Film Transistor (TFT) structures has received increasing attention in the flat panel display industry.
Since sputtering of thick Cu layers has serious disadvantages Flat Panel Display (FPD) manufacturers are considering wet chemical Cu deposition as a viable process alternative. Depending on the required film properties like conductivity and surface roughness either electroless or electrolytical Copper deposition can be applied.
Download complete paper here: pdf file (File size 330 kB)
- Different approaches for improving adhesion on glass
Novel Wet Chemical Copper Metallization for Glass Interposers
Simon Bamberg, Johannes Etzkorn, Frank Brüning, ATOTECH Deutschland GmbH, Erasmusstr. 20, 10553 Berlin, Germany, Ralf Brüning, Physics Department, Mount Allison University, Sackville (NB), Canada, March 2011
Glass as a material for Interposers has significant advantages over silicon and organic substrates in terms of thermal expansion and cost.
Wet-chemical copper deposition is a reliable and competitive method to provide surface and through hole metallization, however sufficient adhesion to the smooth glass substrate is challenging. In order to improve adhesion between glass and metal, various treatments were assessed in this study.
Download complete paper here: pdf file (File size 2.000 kB)
Strain in Electroless Copper Films Monitored by X-ray Diffraction during and after Deposition and its Dependence on Bath Chemistry
Ralf Brüning, Bruce Muir, Eric McCalla, Émilie Lempereur, Physics Department, Mount Allison University, Sackville (NB), Canada, Frank Brüning, Johannes Etzkorn, Atotech Deutschland GmbH, Erasmusstrasse 20, 10553 Berlin, Germany, February 2011
X-ray diffraction based strain measurements have been carried out during the deposition and subsequent relaxation of electroless (autocatalytic) polycrystalline copper films. Thin polymer substrates were mounted on the surface of an electrolyte-filled plating cell, and the X-rays traversed the substrate to scatter of the growing Cu layer. The plating cell was rotated back and forth by up to 70° in order to find the strain of Cu crystallites within and perpendicular to the plane of the film. Three types of plating solutions were investigated. A Ni-free solution C leads to compressive strain during steady-state film growth, followed by an exponential relaxation of the film to a residual tensile strain. Electrolytes A and B contain Ni ions, and the resulting Cu(Ni) films have nearly constant strain with small counteracting strain variations during and after film growth. Cyanide-stabilized solution A yields films with a slight compressive strain, while solution B, stabilized by an aromatic nitrogen compound, yields films with tensile strain. Different and reproducible evolution patterns observed for these three electrolyte types establishes in situ X-ray diffraction strain monitoring as a method to evaluate chemical formulations for electroless deposition.
Download complete paper here: pdf file (File size 680 kB)
- Example of cracking of Cu nanoparticle ink on Borosilicate Glass
Organic and Printed Electronics a View from the traditional Market Place
David Baron, Dr Frank Bruening, Robin Taylor, Atotech Deutschland GmbH, October 2010
For almost ten years, the growing Organic and Printed Electronics (O&PE) community has been advocating the use of Digital Direct Deposition of conductive, semi-conductive and dielectric materials. The focus of this effort has been to replace specific process steps in the existing electronics component manufacturing infrastructure, for example legend Inks in the printed circuit board (PCB) industry, or to provide completely new process sequences for the manufacture of desirable new electronic devices, for example displays based on Organic Light Emitting Diodes. (OLED's).
Download complete paper here: pdf file (File size 640 kB)
- SEM Micrograph of sputtered Mo on Glass
Electroless Copper Metallization for Flat Panel Display Manufacturing
Birgit Beck, Bexy Dosse, Frank Brüning, Johannes Etzkorn, Atotech Deutschland GmbH, December 2010
The feasibility of using wet chemical copper deposition for Thin Film Transistor (TFT) gate metallization was demonstrated to ensure that the initial objectives could be met.
Environmentally friendly processes were then developed that produced adherent copper (Cu) deposits on smooth molybdenum (Mo) layers.
The samples were characterized by means of Interference Microscopy to check Cu distribution and surface roughness.
Conductivity was measured using a 4-Point-Probe conductivity measurement technique.
Focused Ion Beam (FIB) and Scanning Electrode Microscopy (SEM) were used to examine the copper micro-structure and the transition between the Mo-Cu layers.
Finally the Cu deposit adhesion was evaluated using a tape test.
Download complete paper here: pdf file (File size 340 kB)