Multi Material Micro Manufacture Network of Excellence - Laser ablation

Template fabrication incorporating different length scale features

Mon, 04 Aug 2008 14:32:24 +0000

G. Lalev (1), P. Petkov (1), N. Sykes (2), V. Velkova (1), S. Dimov (1), D. Barrow (2)

(1) Manufacturing Engineering Centre, Cardiff University, Newport Road,Cardiff, CF24 3AA, UK
(2) metaFAB, Cardiff University, Newport Road, Cardiff, CF24 3AA, UK

Abstract

A cost effective methodology for pattering of Nano Imprint Lithography (NIL) templates with different length scale features is proposed. The approach relies on selecting the optimum processing window of different technologies for cost effective micro and nano patterning. Very promising results were obtained when first fused silica templates were structured by F2 laser ablation at 157 nm without inducing phase transformation of the material. It was demonstrated that nanoscale features and complex 3D microscale features could be machined with a Focused Ion Beam (FIB) over the existing topography produced by laser ablation. Thus, a large area (up to several square centimetres) of the NIL templates is easily patterned with micro- and even meso-scale features by laser ablation while nano- and micro-scale features could be introduced by FIB machining.

Strategies for material removal in laser milling

Mon, 04 Aug 2008 14:12:36 +0000

P V Petkov, S Scholz and S Dimov
Manufacturing Engineering Centre, Cardiff University, Queen's Buildings, The Parade, Newport Road, Cardiff, CF24 3AA, UK

Abstract

Laser milling with microsecond pulses is a thermal material removal process usually associated with detrimental effects such as heat affected zones (HAZ), a recast layer and debris. Process optimisation can lead to considerable reduction of the above mentioned negative effects. In this context, the research investigates the effects of tool path optimisation and material removal strategies on the resultant surface quality and edge definition. The conducted experimental study shows clearly that the applied milling strategies have a significant effect on the resulting surface topography and the edge definition. Also, the research demonstrates that by optimising the laser path and material removal strategies it is possible to reduce significantly the thermal load when milling micro features, and thus to minimise HAZ and other secondary effects.

Micromachining of amorphous and crystalline Ni78B14Si8 alloys using micro-second and pico-second lasers

Wed, 30 Jul 2008 13:22:59 +0000

I. Quintana (1), T. Dobrev (3), A. Aranzabe (2), G. Lalev (3), S. Dimov (3)

(1) CIC marGUNE. Pol. Ibaitarte 5, 20870; Elgoibar; Guipúzcoa, Spain
(2) Manufacturing Processes Department, Fundación Tekniker, Av. Otaola 20, 2060, Eibar, Guipúzcoa, Spain
(3) Manufacturing Engineering Centre, Cardiff University, Cardiff, CF24 3AA

Abstract

The machining response of amorphous and polycrystalline Ni-based alloys (Ni78B14Si8) to micro-second and pico-second laser processing was investigated. The shape and topography of craters created with single pulses as a function of laser energy together with holes drilled in both materials were studied. The carried out FIB analysis of craters in amorphous and polycrystalline samples revealed that processing both with micro-second and pico-second lasers does not lead to materials crystallization and the short-range atomic ordering of metallic glasses can be retained. When processing the amorphous sample the material laser interactions resulted in a significant ejection of molten material from the bulk that was then followed by its partial re-deposition around the craters. Additionally, there were no signs of crack formation that indicate a higher surface integrity after laser machining. A conclusion is made that laser processing both with short and long pulses is a promising technique for micromachining metallic glasses because does not lead to material crystallisation.

Machining of polystyrene by UV laser radiation for patch clamping device fabrication

Wed, 30 Jul 2008 12:34:35 +0000

S. Wilson (a),(b), W.Pfleging (c), A. Welle (d), P.Kirby (b), M.Przylbyski (e)

(a) Institute for Microstructure Technology, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(b) School of Applied Sciences., Cranfield University, Cranfield, Beds. MK43 0AL, UK
(c) Institute for Materials Research 1, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(d) Institute for Biological Interfaces, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(e) ATL Lasertechnik GmbH, Burger Str. 48, 42929 Wermelskirchen, Germany

Abstract

Laser patterning is of interest for MST applications; direct ablation of polymer material for generating 2D and 3D shapes such as microfluidic channels, curved shapes or micro-holes and alternatively photo-induced change of chemical or physical surface properties. Correct laser choice and process parameters enables new approaches for the fabrication of lab-on-chip devices with integrated functionalities. Laser-assisted ablation and modification of polystyrene (PS) is introduced with respect to the fabrication of polymer devices for high throughput planar patch clamping - a method of measuring the electrical activity of a cell currently a focus for high throughput systems (HTS). There are currently no marketed systems using novel materials that have surface modifications for either individual cell placement, or for dealing with cell networks, a physiologically important consideration for tissue engineering and understanding cell to cell interactions.
Within 4M, a design jointly proposed by FZK and Cranfield University for the fabrication of a polymer patch clamping system, laser micro-drilling of PS and subsequent surface functionalisation for cell adhesion has been investigated as a function of laser and process parameters. High power ArF laser with a pulse of 20 ns as well as high repetition ArF excimer laser sources with pulse lengths of 4-6 ns were used in order to study the influence of laser pulse length on laser drilling and laser induced surface modification. Micro-drilling of PS with diameters down to 1.5 μm have been demonstrated. Furthermore, localized formation of chemical structures suitable for improved single cell and cell network adhesion has been achieved on PS surfaces.

Mircofabrication using a Single Mode Yb Fiber Laser

Tue, 29 Jul 2008 10:36:47 +0000

W. O’Neill, K. Li, Q. Hu, P. Chopra, J. Kanghee, A. Buntardjo
Institute for Manufacturing, University of Cambridge, Cambridge, CB2 1RX, UK

Abstract

The advances in design, performance, cost reduction, and brightness for the modern Yb fiber laser have opened up the possibility of redefining the micro processing options for a range of semiconductor materials and micro fabrication production techniques at a wavelength of 1064nm. The usual laser of choice for micro electronics processing is the 532, 355, or 266 nm DPSS system. The provision of a new MOPA high brightness Yb based fiber laser configuration has provided a range of pulse parameters (10-200 ns FWHM), peak powers approaching ~ 2G Wcm^(-2) , and pulse repetition rates up to 500 kHz. These processing parameters offer a broad range of material response characteristics. This paper provides a preliminary analysis of the use of a Yb based fiber laser in the production of Si and Glassy Carbon microstructures and explores the potential of this source for low cost micromachining solutions.

Micro-machining of Metals, Ceramics and Polymers using Nanosecond Lasers

Tue, 20 May 2008 09:34:50 +0000

M.R.H Knowles, G. Rutterford, D. Karnakis, A. Ferguson
Oxford Lasers Ltd, Unit 8, Moorbrook Park, Didcot, OX11 7HP, UK

Abstract

Laser micro-processing is an enabling technology that facilitates component minaturization and improved performance characteristics. It is being applied across many industries – semiconductor, electronics, medical, automotive, aerospace, instrumentation, and communications. Laser ablation of metals, ceramics and polymers is a complex process and the exact nature of the interaction is specific to the material and laser processing parameters used. Ablation is usually a combination of evaporation and melt expulsion. In order to achieve the highest quality results it is often desirable to minimize the degree of melting involved and short pulse lasers show certain advantages in this respect. We discuss the benefits of high laser intensity (GW/cm)^2 on target for efficient laser micro-fabrication in metals and ceramics. At such high irradiance conditions, material properties are approaching their critical limits and ablation mechanisms are becoming even more complicated but can be exploited to our advantage in particular for high aspect ratio micro-drilling and micro-cutting.

High Power DPSS Laser Micro-Machining of Stainless Steel and Silicon for Device Singulation

Mon, 12 Nov 2007 16:23:32 +0000

D. Karnakis, G. Rutterford, M. R. H. Knowles
Oxford Lasers Ltd., Unit 8, Moorbrook Park, Didcot, Oxfordshire OX11 7HP, UK

Abstract

We describe high power diode-pumped solid-state (DPSS) laser micro-machining results of commonly used industrial materials such as stainless steel and silicon. Frequency up-converted lasers were used at 532nm and 355nm. We discuss the benefits of high laser intensity (~ GW/cm2) micro-machining for efficient laser microfabrication.

At such high irradiance conditions material properties are approaching their critical limits and ablation mechanisms are complex. These can be exploited to our advantage in particular for micro-drilling and micro-cutting small feature sizes in the order 10-20 μm and high aspect ratios of up to 20:1. Etch rate data are presented and a comparative study of the ablation efficiency in these materials is discussed. Results of single shot and multiple shot ablation are also presented. The potential applications of this technology to device singulation for electronic and power generation devices will be described.

Application of Different Process Chains for Polymer Microfluidics Fabrication including Hybrid Tooling Technology

Mon, 12 Nov 2007 16:23:32 +0000

G. Tosello(a), B. Fillon(b), S. Azcarate(c), A. Schoth(d), L. Mattsson(e), C. Griffiths(f), L. Staemmler(g), P.J. Bolt(h)
a: Technical University of Denmark (DTU), Department of Manufacturing Engineering and Management (IPL), 2800 Kgs. Lyngby, Denmark
b: French Atomic Energy Commission (CEA), Laboratory of Innovation for New Energy Technologies and Nanomaterials (LITEN), 38054 Grenoble, France
c: Tekniker Technological Center, 20600 Eibar, Spain
d: University of Freiburg, Institute of Microsystem Technology (IMTEK), 79110 Freiburg, Germany
e: School of Industrial Technology and Management (KTH), Department of Production Engineering, 100 44 Stockholm, Sweden
f: Cardiff University, Manufacturing Engineering Center (MEC), Cardiff CF 24 3AA, UK
g: Hahn-Schickard-Gesellschaft, Institute for Micro Assembly Technology (HSG-IMAT), 70174 Stuttgart, Germany
h: TNO Science & Industry, 5600 HE Eindhoven, The Nederlands

Abstract

This paper is based on the Division 4 “Processing of Polymers” activities within the 4M NoE “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (μ-milling, μ-EDM, laser μ-machining, electrochemical μ-milling). The micro tools were then tested with different polymers. The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finishing, and aspect ratios of both micro tools and micro moulded parts.

Short Pulse Laser Milling effects on Surface Integrity

Mon, 12 Nov 2007 16:23:32 +0000

P V Petkov, S S Dimov, R. Minev and D T Pham
Manufacturing Engineering Centre, Cardiff University, Queen’s Building, Newport Road, The Parade, Cardiff, CF24 3AA, UK

Abstract

Laser milling of engineering materials is a viable alternative to conventional methods for machining complex micro components. The laser source employed to perform such micro structuring has a direct impact on achievable surface integrity. At the same time, the trade offs between high removal rates and the resulting surface integrity should be taken into account when selecting the most appropriate ablation regime for performing laser milling. In this paper the effects of pulse duration on surface quality and material microstructure are investigated when ablating a material commonly used for manufacturing micro tooling inserts. When performing ultra short pulsed laser ablation some heat is dissipated into the bulk but not sufficient to trigger significant structural changes.

Feasibility study for microfluidic separation device for biological fluids

Mon, 02 Apr 2007 14:10:43 +0000

4M Partner:
Imego AB

4M Partner No:
18

Collaborator Name:
Denator AB

Proposal for extended project to RAS:
Yes

Technology enquiry/solution sought:

The study requested is a preparation for a possible research and development project of a product that can perform fast separation and inactivation of biological fluids. Proteins, peptides and metabolites are rapidly degraded after extraction, which causes large problems for both academic and industrial protein research. In this study, Imego will investigate the feasibility of fabricating low-cost glass and polymer chips that combine microfluidic separation with Denator’s proprietary preservation technology.

USTUTT

Tue, 30 Jan 2007 13:05:53 +0000

Facilities/Hardware:

Sensors and actuators based on metallized polymers, precision micro injection moulding, environmental testing
website: www.uni-stuttgart.de/izfm

RAS contact:
kueck

Thu, 01 Jan 1970 00:00:00 +0000

n/a

University of Naples Federico II

Wed, 10 Jan 2007 17:14:33 +0000

Facilities/Hardware:

Manufacturing processes and simulation
Contact and non-contact reverse engineering
Rapid product development
2D and 3D metrology systems
Advanced materials mechanical characterisation
Metallographic analysis
Nondestructive testing and evaluation
Intelligent sensor systems

RAS contact:
tetiro

Laser system for micro fabrication

Fri, 27 Oct 2006 16:19:56 +0000

4M Partner:
University of Naples Federico II

4M Partner No:
25

Collaborator Name:
Lasit Srl

Proposal for extended project to RAS:
Yes

Technology enquiry/solution sought:

Lasit is a high tech SME specialising in development and applications of Nd:YAG laser system for the mechanical manufacturing industry that has had long term collaborations with the University of Naples Federico II in the field of laser manufacturing applications. Lasit recently submitted a technological enquiry regarding the identificaion of problems in the development and optimisation of Nd:YAG laser systems for micro fabrication processes such as micro drilling and micro engraving for the mechanical and aerospace industries.

Laser microdrilling optimisation

Fri, 27 Oct 2006 12:43:22 +0000

4M Partner:
University of Naples Federico II

4M Partner No:
25

Collaborator Name:
RTM SpA

Proposal for extended project to RAS:
Yes

Technology enquiry/solution sought:

RTM is a private research centre that has had long term collaborations with the University of Naples Federico II in fields of material processing and metrology, welding, material characterisation, etc. RTM recently submitted a technological enquiry regarding the ptimization of a laser microdrilling process through a DOE plan and material characterisation procedures.