Analysis of Silicon Micromachining by UV Lasers, and Implications for Full Cut Laser Dicing of Ultra-Thin Semiconductor Device Wafers

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001743-001759
Author(s):  
Andy Hooper ◽  
Daragh Finn
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Semiconductor Device ◽  
Laser Pulses ◽  
Silicon Wafers ◽  
Silicon Devices ◽  
Laser Fluences ◽  
Slow Velocity ◽  
3D Packaging ◽  
Thin Silicon

3D packaging technologies such as FLASH rely on die-to-die stacking of ultra-thin silicon devices with individual die thicknesses below 100 um. Because ultra-thin silicon wafers are very fragile, mechanical saw dicing of sub 100 um thick wafers tends to be more challenging, requiring slower processing and reduced throughput and/or yields. These challenges make full cut laser dicing an attractive solution. This presentation provides an investigation for machining of 50 um thick silicon wafers using a Gaussian-shaped, nanosecond pulsewidth, 355 nm UV laser. A range of machining speeds and laser fluences are compared, from single laser pulses to highly overlapped slow-velocity machining. 3D Laser Scanning Microscope and FIB/TEM cross sections are employed to characterize the state and depth of heating damage into the Si material. Implications for laser machining rates and die break strength are investigated for full cut laser dicing.

Behavior of contact-silicided TFSOI gate structures

1994 ◽  
Vol 52 ◽  
pp. 860-861
Author(s):  
N. David Theodore ◽  
Juergen Foerstner ◽  
Peter Fejes
Keyword(s):  
Semiconductor Device ◽  
Series Resistance ◽  
Field Effect Transistors ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
Continuous Layer ◽  
Buried Oxide ◽  
Device Structures ◽  
Thin Silicon

As semiconductor device dimensions shrink and packing-densities rise, issues of parasitic capacitance and circuit speed become increasingly important. The use of thin-film silicon-on-insulator (TFSOI) substrates for device fabrication is being explored in order to increase switching speeds. One version of TFSOI being explored for device fabrication is SIMOX (Silicon-separation by Implanted OXygen).A buried oxide layer is created by highdose oxygen implantation into silicon wafers followed by annealing to cause coalescence of oxide regions into a continuous layer. A thin silicon layer remains above the buried oxide (~220 nm Si after additional thinning). Device structures can now be fabricated upon this thin silicon layer.Current fabrication of metal-oxidesemiconductor field-effect transistors (MOSFETs) requires formation of a polysilicon/oxide gate between source and drain regions. Contact to the source/drain and gate regions is typically made by use of TiSi2 layers followedby Al(Cu) metal lines. TiSi2 has a relatively low contact resistance and reduces the series resistance of both source/drain as well as gate regions

scholarly journals Analysis of Damage Thresholds of Laser Scanning Mirrors using Ultrashort Laser Pulses

2011 ◽  
Vol 12 ◽  
pp. 445-451 ◽  
Author(s):  
Claus Dold ◽  
Gregory Eberle ◽  
Konstantins Jefimovs ◽  
Markus Axtner ◽  
Frank Pude ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ultrashort Laser

scholarly journals Application Examples for the Different Measurement Modes of Electrical Properties of the Solar Cells

2014 ◽  
Vol 59 (1) ◽  
pp. 247-252 ◽  
Author(s):  
M. Musztyfaga-Staszuk ◽  
L.A. Dobrzanski ◽  
S. Rusz ◽  
M. Staszuk
Keyword(s):  
Solar Cells ◽  
Electrical Properties ◽  
Contact Resistance ◽  
Sheet Resistance ◽  
Cross Sections ◽  
Standard Technique ◽  
Photovoltaic Cell ◽  
Metal Resistance ◽  
Silicon Wafers ◽  
Formation Technique

Abstract The aim of the paper was to apply the newly developed instruments ‘Corescan’ and ‘Sherescan’ in order to measure the essential parameters of producing solar cells in comparison with the standard techniques. The standard technique named the Transmission Line Method (TLM) is one way to monitor contacting process to measure contact resistance locally between the substrate and metallization. Nowadays, contact resistance is measured over the whole photovoltaic cell using Corescanner instrument. The Sherescan device in comparison with standard devices gives a possibility to measure the sheet resistance of the emitter of silicon wafers and determine of both P/N recognition and metal resistance. The Screen Printing (SP) method is the most widely used contact formation technique for commercial silicon solar cells. The contact resistance of manufactured front metallization depends of both the paste composition and co-firing conditions. Screen printed front side metallization and next to co-fired in the infrared conveyor furnace was carried out at various temperature from 770°C to 920°C. The silver paste used in the present paper is commercial. The investigations were carried out on monocrystalline silicon wafers. The topography of co-fired in the infrared belt furnace front metallization was investigated using the atomic force microscope and scanning electron microscope (SEM). There were researched also cross sections of front contacts using SEM microscope. Front contacts of the solar cells were formed on non-textured silicon surface with coated antireflection layer. On one hand, based on electrical properties investigations using Sherescan instrument it was obtained the knowledge of the emitter sheet resistance across the surface of a wafer, what is essential in optimizing the emitter diffusion process. On the other hand, it was found using Corescan instrument that the higher temperature apparently results in a strongly decreased contact resistance.

Wafer-Scale, Highly-Ordered Silicon Nanowires Produced by Step-and-Flash Imprint Lithography and Metal-Assisted Chemical Etching

2012 ◽  
Vol 1512 ◽  
Author(s):  
Jian-Wei Ho ◽  
Qixun Wee ◽  
Jarrett Dumond ◽  
Li Zhang ◽  
Keyan Zang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Semiconductor Device ◽  
Imprint Lithography ◽  
Wafer Level ◽  
Conventional Photolithography ◽  
Metal Assisted Chemical Etching

ABSTRACTA combinatory approach of Step-and-Flash Imprint Lithography (SFIL) and Metal-Assisted Chemical Etching (MacEtch) was used to generate near perfectly-ordered, high aspect ratio silicon nanowires (SiNWs) on 4" silicon wafers. The ordering and shapes of SiNWs depends only on the SFIL nanoimprinting mould used, thereby enabling arbitary SiNW patterns not possible with nanosphere and interference lithography (IL) to be generated. Very densely packed SiNWs with periodicity finer than that permitted by conventional photolithography can be produced. The height of SiNWs is, in turn, controlled by the etching duration. However, it was found that very high aspect ratio SiNWs tend to be bent during processing. Hexagonal arrays of SiNW with circular and hexagonal cross-sections of dimensions 200nm and less were produced using pillar and pore patterned SFIL moulds. In summary, this approach allows highlyordered SiNWs to be fabricated on a wafer-level basis suitable for semiconductor device manufacturing.

A Practical Computing Method for Residual Area of Rebar Cross-Sections under Carbonation Induced Corrosion

2012 ◽  
Vol 166-169 ◽  
pp. 1895-1899
Author(s):  
Xiao Gang Wang ◽  
De Ming Zhong
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Major Axis ◽  
Structural Deterioration ◽  
Minimum Residual ◽  
Degree Of Confidence ◽  
Conservative Approximation ◽  
Rc Slabs ◽  
Computing Method ◽  
Geometric Measurement

Area loss of severely weakened rebar cross sections is a crucial variable in assessment of structural deterioration for corroded concrete structures, which is hard to be measured or estimated precisely in conventional methods. In this paper, rebar samples were taken from naturally corroded RC slabs. Their virtual models were built using 3D laser scanning technique to facilitate geometric measurement. From these models seriously weakened sections were screened out as analyzing samples, and residual areas as well as profiles of the cross-sections were derived and investigated consequently. Shown by the results, corrosion was non-uniformly distributed on rebar surface, and profiles of the residual cross-sections can hardly be formulated efficiently. However, they can be simplified into ellipse with minor axis of minimum residual diameter and major axis of diameter in perpendicular direction. This model has been proved to give an conservative approximation of residual sectional area with 4.27% underestimation and 89.2% degree of confidence.

scholarly journals Cell Adherence and Drug Delivery from Particle Based Mesoporous Silica Films

2019 ◽  
Author(s):  
Emma Björk ◽  
Bernhard Baumann ◽  
Florian Hausladen ◽  
Rainer Wittig ◽  
mika lindén
Keyword(s):  
Drug Delivery ◽  
Laser Scanning ◽  
Single Cells ◽  
Silicon Wafers ◽  
Laser Scanning Microscopy ◽  
Drug Uptake ◽  
C2c12 Cells ◽  
Confocal Laser ◽  
Particle Sizes

Spatially and temporally controlled drug delivery is important for implant and tissue engineering applications, as the efficacy and bioavailability of the drug can be enhanced, and can also allow for drugging stem cells at different stages of development. Long-term drug delivery over weeks to months is however difficult to achieve, and coating of 3D surfaces or creating patterned surfaces is a challenge using coating techniques like spin- and dip-coating. In this study, mesoporous films consisting of SBA-15 particles grown onto silicon wafers using wet processing were evaluated as a scaffold for drug delivery. Films with various particle sizes (100 – 900 nm) and hence thicknesses were grown onto OTS-functionalized silicon wafers using a direct growth method. Precise patterning of the areas for film growth could be obtained by local removal of the OTS functionalization through laser ablation. The films were incubated with the model drug DiO, and murine myoblast cells (C2C12 cells) were seeded onto films with different particle sizes. Confocal laser scanning microscopy (CLSM) was used to study the cell growth, and a vinculin-mediated adherence of C2C12 cells on all films was verified. The successful loading of DiO into the films was confirmed by UV-vis and CLSM. It was observed that the drugs did not desorb from the particles during 24 hours in cell culture. During adherent growth on the films for 4 h, small amounts of DiO and separate particles were observed inside single cells. After 24 h, a larger number of particles and a strong DiO signal were recorded in the cells, indicating a particle mediated drug uptake. A substantial amount of DiO loaded particles were however attached on the substrate after 24 making the films attractive as a long-term reservoir for drugs on e.g. medical implants.<br>

Surface hardening of SUS304 by irradiation with a KrF excimer laser in SiH4 gas ambient

1990 ◽  
Vol 5 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Koji Sugioka ◽  
Hideo Tashiro ◽  
Koichi Toyoda ◽  
Eiichi Tamura ◽  
Keigo Nagasaka
Keyword(s):  
Excimer Laser ◽  
Surface Hardening ◽  
Continuous Distribution ◽  
Surface Hardness ◽  
Laser Pulses ◽  
High Concentration ◽  
Laser Fluences ◽  
High Adhesion ◽  
Krf Excimer Laser ◽  
Si Films

Surface hardening of SUS304 resulting from the process of doping and deposition of Si by irradiation of a KrF excimer laser beam in a SiH4 gas ambient is investigated, and variations of the surface hardness are examined for different numbers of laser pulses and the laser fluences. The hardening is due to Si incorporation in high concentration. The continuous distribution of Si atoms across the surface layer suggests that a very high adhesion strength of the deposited Si films can be formed. The specific process for surface modification is referred to as laser implant-deposition (LID).

Backside Thinning and Stress-Relief Techniques for Thin Silicon Wafers

2014 ◽  
pp. 207-226
Author(s):  
Christof Landesberger ◽  
Christoph Paschke ◽  
Hans-Peter Spöhrle ◽  
Karlheinz Bock
Keyword(s):  
Stress Relief ◽  
Silicon Wafers ◽  
Thin Silicon
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