Ultrafast laser welding of ceramics

Welding of ceramics is a key missing component in modern manufacturing. Current methods cannot join ceramics in proximity to temperature-sensitive materials like polymers and electronic components. We introduce an ultrafast pulsed laser welding approach that relies on focusing light on interfaces to ensure an optical interaction volume in ceramics to stimulate nonlinear absorption processes, causing localized melting rather than ablation. The key is the interplay between linear and nonlinear optical properties and laser energy–material coupling. The welded ceramic assemblies hold high vacuum and have shear strengths comparable to metal-to-ceramic diffusion bonds. Laser welding can make ceramics integral components in devices for harsh environments as well as in optoelectronic and/or electronic packages needing visible-radio frequency transparency.

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Organic Light Emitting Material Direct Writing by Nanomaterial Enabled Laser Transfer

MRS Proceedings ◽

10.1557/proc-1179-bb06-31 ◽

2009 ◽

Vol 1179 ◽

Author(s):

Seung Hwan Ko ◽

Heng Pan ◽

Nipun Misra ◽

Costas Grigoropoulos

Keyword(s):

Mass Production ◽

Laser Energy ◽

Light Emitting Diode ◽

Nanoparticle Size ◽

Temperature Sensitive ◽

Conductive Heat ◽

Direct Writing ◽

Light Emitting ◽

Laser Transfer ◽

Organic Light

AbstractOrganic light emitting material direct writing is demonstrated based on nanomaterial enabled laser transfer. Through utilization of proper nanoparticle size and type, and the laser wavelength choice, a single laser pulse could transfer well defined and arbitrarily shaped tris-(8-hydroxyquinoline)Al patterns ranging from several microns to millimeter size. The unique properties of nanomaterials allow laser induced forward transfer at low laser energy (0.05 J/cm2) while maintaining good fluorescence. The technique may be well suited for the mass production of temperature sensitive organic light emitting devices.The combined effects of melting temperature depression, lower conductive heat transfer loss, strong absorption of the incident laser beam, and relatively weak bonding between nanoparticles during laser irradiation result in the transfer of patterns with very sharp edges at relatively lower laser energy than commonly used, thus inducing minimal damage to the target organic light emitting diode material with no evidence of cracks. This technique can be applied to a broad range of laser wavelengths with proper selection of nanoparticle size and size distribution, as well as the material type. Additionally, nanomaterial enabled laser transfer may be particularly advantageous for the mass production of temperature sensitive devices.

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Structural and Tribological Properties of TiC/C/Ag Coatings in Vacuum and Ambient Environments

MRS Proceedings ◽

10.1557/proc-697-p8.1 ◽

2001 ◽

Vol 697 ◽

Cited By ~ 2

Author(s):

Jose L. Endrino ◽

Jose J. Nainaparampil ◽

James E. Krzanowski

Keyword(s):

Carbon Content ◽

Laser Energy ◽

High Vacuum ◽

Ambient Conditions ◽

Friction Behavior ◽

Cross Sectional ◽

Reduced Modulus ◽

Custom Made ◽

Disk Friction ◽

Pin On Disk

AbstractTiC/C/Ag coatings were deposited by magnetron sputtering pulsed laser deposition (MSPLD) combining sputtering from a custom made Ti-Ag (60:40) target with the ablation of carbon. Energy disperse spectroscopy (EDS) was used to determine the elemental composition, and x-ray diffraction (XRD) and cross-sectional scanning electron microscopy (XSEM) to examine the structure of the films. Hardness and reduced modulus measurements were acquired using a nanoindentation technique. The pin-on-disk friction test was used to study the friction behavior of the deposited samples in high vacuum and ambient conditions. Variations in the laser energy and the power of the sputtering gun yielded a set of samples with carbon content that ranged from 15.0 to 95.6 percent. The hardest samples with the highest reduced modulus were those with a moderate carbon content and that were shown to form a titanium carbide phase. Tribological results indicated that there is an optimum composition of a TiC/C/Ag coating (~25 at.% carbon) for which it can be reversible and provide lubrication in both ambient and vacuum.

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Laser welding of Cu wires bundle and dumet wire for interconnection of electronic components

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY ◽

10.2207/qjjws.24.191 ◽

2006 ◽

Vol 24 (3) ◽

pp. 191-199

Author(s):

Shoji SASAKI ◽

Kohsuke TAGASHIRA ◽

Koji SAITO ◽

Tsuyoshi TEMMA ◽

Makoto ORIKAWA ◽

...

Keyword(s):

Laser Welding ◽

Electronic Components

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Characteristics of the Keyhole and Energy Absorption during YAG Laser Welding of Al-Li Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.287-290.2401 ◽

2011 ◽

Vol 287-290 ◽

pp. 2401-2406 ◽

Cited By ~ 1

Author(s):

Ai Qin Duan ◽

Shui Li Gong

Keyword(s):

Laser Welding ◽

Heat Input ◽

High Speed ◽

Laser Energy ◽

Welding Parameters ◽

High Speed Camera ◽

Welding Time ◽

Welding Condition ◽

Yag Laser ◽

Temperature Area

In this paper, the keyhole of YAG laser welding 5A90 Al-Li alloy was observed and measured through the high speed camera. The characteristics of the keyhole and the effects of welding parameters were studied. The characteristics of the absorption of laser energy and the susceptivity for heat input in welding 5A90 were given. The results show that in this welding condition, the keyhole of laser welding 5A90 is nearly a taper and the highest temperature area is in the bottom. There are clear effects of heat input on the characteristics, especially the surface radius of keyhole and plasma/vapor in keyhole. Another phenomena is observed that sometime plasma/vapor could disappear in 0.3ms welding time, and this feature will be more remarkable as decrease of heat input. It shows that the absorption of energy is unsteady. It is known that when this instability reaches a certain value, an unsteady weld will be formed.

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Effects of active flux on plasma behavior and weld shape in laser welding of X5CrNi189 stainless steel

Modern Physics Letters B ◽

10.1142/s0217984916503759 ◽

2016 ◽

Vol 30 (31) ◽

pp. 1650375 ◽

Cited By ~ 1

Author(s):

Hongbin Dai ◽

Jun Peng

Keyword(s):

Stainless Steel ◽

Laser Welding ◽

Laser Plasma ◽

Laser Energy ◽

Weld Zone ◽

Welding Process ◽

Width Ratio ◽

Weld Depth ◽

Active Flux ◽

Plasma Behavior

In this paper, stainless steel was welded by active flux-aided laser welding method. The effects of single active flux (Cr2O3, SiO2 and TiO2) and composite active flux on laser welding were studied. In the welding process, laser plasma behavior was recorded by a high-speed imaging system. The results show that, with the addition of active flux, the absorption of laser energy and melting efficiency increase. In the laser power of 750 W, effects of active flux on weld depth to width ratio are given by the order: composite active flux [Formula: see text] SiO[Formula: see text] Cr2O[Formula: see text] TiO2. The effect of composite active flux is the most significant and it can increase the weld depth to width ratio to 85%. Active flux can restrict the laser plasma. With the addition of composite active flux, the projected area of laser plasma obtained obviously reduced, and it can be reduced by 41.39%. Active flux cannot obviously change the main components in weld zone, but can change the grains of austenite and ferrite.

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High temperature Au-based solder reliability in electronic packages for harsh environments

International Symposium on Microelectronics ◽

10.4071/isom-2011-tp6-paper6 ◽

2011 ◽

Vol 2011 (1) ◽

pp. 000438-000445

Author(s):

M.F. Sousa ◽

S. Riches ◽

C. Johnston ◽

P.S. Grant

Keyword(s):

High Temperature ◽

Thermal Cycling ◽

Thermal Shock ◽

Microstructural Analysis ◽

Temperature Stability ◽

Acoustic Microscopy ◽

Harsh Environments ◽

Electronic Packages ◽

High Temperature Stability ◽

Die Attach

The operation of electronic packages in high temperature environments is a significant challenge for the microelectronics industry, and poses a challenge to the traditional temperature limit of 125°C for high electronic systems, such as those used in down-hole, well-logging and aero-engine applications. The present work aims to develop understanding of how and why attach materials for Si dies degrade/fail under harsh environments by investigating high temperature Au based solders. Au-2wt%Si eutectic melts at < 400°C and offers high temperature stability but high temperature processing and complex manufacturing steps are the major drawbacks. Changes in the die attach material were investigated by isothermal ageing at 350°C, thermal shock and thermal cycling treatments. Die attach reliability investigated by thermal shock and thermal cycling showed that the bonded area degraded. Nevertheless, most of the samples tested had high bonded area ranging from 92.5 to 97.5%. The failure behaviour of the die attach materials included cracking of die and/or attach material, delamination and voiding. Scanning acoustic microscopy images provided a rapid assessment of delamination and other defects and their location within the package. Microstructural analysis and die shear testing were also carried out, along with the high temperature endurance of a SOI test chip for signal conditioning and processing applications at 250°C. All functions evaluated have shown stable performance at 250°C for up to 9000 hours.

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