SanDisk tinkers with Matrix 3D Memory

Several weeks ago, I discussed an Ottawa firm’s entry into the one-time programmable (OTP) memory space. My focus in that discussion was the Matrix 3D memory which was also OTP and a rather ingenious way of packing very high numbers of bits onto chips made with older process technology – very old in comparison with the 50nm technology in use today at IMFT. I believed that the OTP concept was a good one for digital film or copyrighted content like movies or music. However, SanDisk has not heeded my advice and announced that they are working on “how we evolve that 3D technology from a one-time-programmable to a read-writable type of memory”. For clarity, I think the intention was to describe this as a “re-writable” memory.

Putting aside my disagreements with the SanDisk product management philosophy, I don’t quite get how this is possible. Without some fundamental change to the concept developed by Matrix, it is not. High-ranking Matrix employees noted to me that it would be impossible to revert a Matrix OTP fuse element fabricated at TSMC once programmed or “fused”. This completely aligned with what we saw in our independent analysis of those fuse structures as well. Short of destroying the chip, those stored bits are quite safe.

Maybe SanDisk engineers are considering MRAM? At least there would be a similarity based on the cells sitting between metal lines. If Sandisk makes an MRAM at the same bit cell density that the Matrix 3D OTP memory allowed, let me be the first to nominate them for the Nobel Prize.

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