Saloma
Saloma
The US Patent and Trademark Office (USPTO) recently granted a patent to a method devised by scientists from the University of the Philippines Diliman (UPD) that can determine the precise location of defects in an integrated circuit (IC).
Developed by professors Dr. Caesar A. Saloma, Dr. Vincent Ricardo M. Daria and Dr. Jelda Jayne C. Miranda of the National Institute of Physics (NIP), the patented invention is a method that permits the generation of high-contrast images of semiconductor sites in an integrated circuit sample. It utilizes the one-photon beam-induced current (1P-OBIC) image and confocal reflectance image of the sample, both of which are generated simultaneously from one and the same light beam focused on the same sample.
“An IC failure analysis equipment that utilizes our method will be relatively inexpensive to acquire and maintain,” Saloma, who is currently dean of the College of Science claims.
An IC is a miniaturized electronic circuit consisting mainly of semiconductor devices (transistors and pn junctions) and passive components (capacitor, etc.) manufactured on the surface of a thin substrate of a semiconductor material.
Stressing the importance of ICs in everyday life, Saloma explained, “Today, it is quite hard to think of a device, equipment, or appliance that does not use a microprocessor--an example of an IC--for reliability, accuracy, and precision. Even Meralco has replaced its old mechanical power meters with digital ones.”
Thus, failure analysis is a critical aspect in the manufacture of IC devices. Before a new IC device is produced commercially, its prototype undergoes failure analysis to determine locations in the IC where defects are most likely to happen.
“Defect detection at the prototype level saves on manufacturing cost and avoids unfavorable IC device reviews,” Saloma said.
Locations where defects can occur are called hotspots or cold spots since their temperatures are hotter or colder than the average IC temperature.
The patented method utilizes the physical phenomenon that when light of a suitable color illuminates a semiconductor material, it causes an electrical current to flow in the material. Thus, an OBIC image of an IC will look brighter than the metal and a defect will contain a dark spot in the OBIC image, meaning no current is flowing.
The scientists first filed for a US Patent (via PCT/PH02/0013) on July 9, 2002 with the title,"Method for generating high contrast images of semiconductor sites via one-photon optical beam induced current imaging and confocal reflectance microscopy." The USPTO issued the patent (US Patent No. 7,235,988) on 26 June 2007. The patent application process was handled by the UPD Office of the Vice Chancellor for Research and Development and the Villaraza & Angangco Law Offices.
“The patented method is a generic technique that has already led to other derivative applications that we have tested in our research laboratory at the NIP. Widely-circulated technology magazines like that Photonics Spectra and MRS Bulletin have featured our research works indicating their potential usefulness in the semiconductor industry,” Saloma pointed out.
Saloma considers the USPTO patent crucial because the US “is the most important single economy in the world at least for the moment.” In addition, it represents the culmination of a long, expensive process that starts with scientific research and development.
Presently, the group plans to “generate wealth” out of the invention, a task that they actually consider harder to accomplish than getting a US patent.”The generated wealth will be utilized to enhance the academic reputation of the University of the Philippines in the ASEAN region and the rest of the world.”
Presently, the scientists are in discussion with parties interested in producing an equipment based on the patented method.