TEM Technology to Improve VCD, DVD Yields
nikkeibp.asiabiztech.com
The Institute of Microelectronics (IME) of Singapore is developing a
transmission electron microscopy (TEM) technology to improve the yield and
quality in the production of video compact disks (VCD) and digital video discs
(DVD). This is part of the institute's ongoing research and development efforts.
Recently it signed an agreement with 11 multinational and Singapore
companies to form a consortium to research and develop technologies for the
packaging of next-generation integrated circuits.
According to George Sheng, IME's senior member, technical staff, failure
analysis and reliability, the application of TEM technology could be very
important for the VCD and DVD industry as the density of the discs becomes
higher. He said without TEM technology, it would be very difficult to conduct
any detailed study of the microstructure of the discs.
Sheng said the application of TEM technology to VCDs and DVDs was
similar to that applied to semiconductor devices. "At first, it was just for
research purposes, to prove some point. But now, every step of the process
requires TEM and I think eventually every VCD manufacturer will have to use
the TEM process," he said.
The use of TEM technology in the semiconductor industry has enabled the
identification of bonding faults and material impurities and the evaluation of
metal coverage and layer interfaces. TEM is also recognized as an essential
diagnostic tool in microelectronics and photonics. Sheng said IME was among
the first in the world to use TEM to study and understand the physics behind
the technology of under bump metallization (UBM), the key technology in
advanced packaging technology such as flip chip and multichip module.
Cross-Sectioning a Disc
He said previously it was almost impossible to obtain a cross-section sample
of DVD materials to study the internal structure of the discs, since the thin
structure film of the discs is sandwiched between two thick polycarbonate
layers. He added that the ability to remove the polycarbonate layers without
damaging the structure film of the discs was the key to making a successful
sample.
Sheng said by comparison, it's more difficult to make a cross-section of the
discs than semiconductor circuits because the discs are plastic and the material
has to be dissolved in solvent. "First, we have to try to mechanically remove
the plastic layer and reach the actual structure film layer; then we dissolve the
plastic layer materials; and finally, we make a cross-section of the film layer.
The difficulty lies with the plastic layer," said Sheng.
The ability to remove the polycarbonate layers while leaving the structure film
layer enables successful TEM analysis. A sample micrograph of a DVD could
thus be produced, showing the detailed microstructure of the DVD; this cannot
be observed by other techniques. On other applications of TEM technology by
IME, Sheng said that the institute has provided TEM analysis service to its
clients on blue laser GaN materials and devices used in optoelectronics.
Also in the field of optoelectronics, IME is cooperating with the Chinese
Academy of Science in Beijing, China, on the use of TEM technology in the
study of self assembled quantum dot materials. He said that IME is also using
TEM technology to study the process issues in micro electrical mechanical
systems (MEM) such as microsensors, micro-accelerometers and
microphones.
Sheng, one of the five winners for the Philips Anniversary Image Contest held
in 1999 in the Materials Science category, is the pioneer of the 1974
development of cross-sectioning of samples for TEM studies of semiconductor
devices. He has also contributed to other major projects in Bell Labs of the
US, and developed TEM as an essential diagnostic tool in the research,
development and manufacture of semiconductor devices.
(Robert Yaw, Singapore: Feb. 2000 Issue, Nikkei Electronics Asia) |
