October 19, 2017
A new cost-saving design methodology for laser systems
Published in 1898, The War of the Worlds by H.G. Wells pitted Martians against humans. The aliens were armed with weapons that read a lot like lasers. Though the first operational laser wouldn’t appear for decades, today, H.G. Wells would be proud. Lasers of all kinds are increasingly being used in the defense, consumer electronics, automotive, scientific research, and medical device industries. They’re even being used to make sure the memory on your smartphone works properly.
Memory repair is critical in the production of advanced computer memory like DRAM and NAND chips, which are in everything from modern computers to the iPhone 8. Each chip consists of billions of cells, which correspond to gigabytes of memory. Each cell can store a single zero or one. But the production process isn’t perfect and some cells don’t work. For that reason, all cells need to be tested, and the bad cells destroyed.
After identifying the bad cells in a chip, the corresponding memory link fuses are blown to prevent the computer from accessing any of the bad cells. Laser pulses are one way to destroy the bad cells. However, the procedure requires utmost precision: Each pulse must be strong enough to reliably blow faulty fuses, but not so strong that it could damage neighboring links.
Electro Scientific Industries (ESI), a creator of laser-based manufacturing solutions primarily for the semiconductor and consumer electronics industry, developed a new, cost-saving methodology to deliver the required ultra-small spot size for the job—down to 1.4 um with a 1 um wavelength laser.
To confirm the methodology prior to production, ESI turned to OpticStudio. “Because we could no longer solve this analytically, we used OpticStudio to show that the behaviors that we anticipated stayed the same in all cases,” said Dr. Jan Kleinert, Laser & Optics Engineering Manager at ESI. “Modeling many scenarios in OpticStudio gave us confidence that our theory would work in the real world.”
By validating this methodology, ESI has relaxed laser specification requirements despite the precision required, thereby reducing manufacturing costs of their ultra-precise micromachining systems. It also gives suppliers more margin in their design and specifications without compromising the performance of ESI’s memory repair systems.
Read more about the cost-saving methodology for laser design.
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