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Light emitting diode process in 2003 & the equipment
development trend
| Since its debut, the development
of the light-emitting diodes has taken to two extremes of being
micro and macro, which essentially refers to the need for varied
size of the LED chip, as the two have taken to distinct application
paths and with equal demands to match. Where the macro applications
have taken to lighting, with a power consumption of 4 to 5 watts
for luminance of 1 watt and higher, which has a key technology
built upon wafer bonding and ventilated packaging technology.
Whereas the macro applications take to a power 0.1watt, 0.5m
candlelight luminance that have a key technology rests on ITO
see-through diode and surface etching. The polarized development
trend would poised to challenge the mid- and upstream LED producers
and equipment makers in that more research is needed to grasp
dependability and reliability as the key to mass-produced process
and equipment making, and a technical determinant for many of
the LED makers in 2003. |
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To gauge from the development of
the micro trend, its very essence lies in brining out more light
from the chipset, which is often accomplished through Nome surface
etching via RIE, ICP-RIE or reactive
ion milling, with uniformity comes a second determinant. And
unlike the conventional dry plastic etching taking to a flat
surfacing, the Nome coarseness rated technology has had its
process control revamp from the previous chemical etching to
a physicality oriented one focusing on a voluntary saturation
reaction, which poises to increase the light emission by approx.
15%. While for ITO see-through electrode, an ITO membrane is
formed via E-beam Evaporator or Electromagnetic
Sputter at a 200 to 400 ¢J. Celsius environment to achieve
an effective membrane penetration rate of greater than 80% and
an impedance rate of less than 20 ohms per square feet to increase
the light emission by approx. 20%. The foregoing analysis yields
a fast that the ability to combine the two techniques would
poised to increase the LED luminance by over 30%, which to the
human eye would be twice as bright to unquestioningly trigger
a new wave of technology and marketing wrestle in 2003 as a
new niche to the equipment producers. |
And as to the development of the
macro trend, its key lies in interpreting the heat ventilating
technique, which would compel that both the GaAs substrate and
window layer would have to be reevaluated for their adequacy.
In which, the Wafer Bonding System Wafer
Bonding System derived from the SOI technology has since
been adopted in the current processing for optimizing the success
rate and in metal bonding using heat conducive silica substrate
metal sub-mount to replace the GaAs and the Al2O3 techniques.
Meanwhile, its application in the heat conductive packaging
technique adopted for laser diode and power device packaging
applications has emerged as a growing trend to lead to a market
segregation, whether it be for changes in packaging techniques
following the substitution of indium alloy in place of epoxy,
or the adaptation of a Micro Tubing, let along the constant
breakthrough in equipment making technology.
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Following the revolutionary debut of the day
glow LLED in 2002, indubitably there will be more producers
jumping on the bandwagon to continue the R&D in this domain
with substantial efforts and manpower, while the day glow LED
that rests on Electromagnetic Sputter
ITO and Wafer Bonding techniques will
soon shine brightly by 2008! |
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