Nanopierce Technologies (NPCT)

[greg s]

John,

First, what I am about to say isn't about the goodness or badness of the Nanopierce technology. That would require a LOT more study than I have time for right now.

I did go over to the Nanopierce site to understand exactly what the company is doing. I think I need to give you some guidance, so your own study can be more fruitful (hope you don't mind!)

RE your comment: "I'm working from pure recollection at the moment, but I recall the conductor separation on the substrate of SRAM and DRAM chips at White Oak to be about 0.6 Microns."

This refers to the construction of the semiconductor die (individual die are created on a silicon wafer, probed (tested), sorted, then the wafer is sawed into individual die).

Nanopierce's main thrust is "flip chip" technology. This deals with how these die are mounted (assembled) either directly to a substrate (board) or to a package. Each die has "pads" which much be connected to the outside world. For a simple view, think of the old "DIP" or dual inline package. When you look at a circuit board, you see a bunch of packaged IC's along with a bunch of resistors, capacitors, etc. The DIP's are the larger rectangular devices with leads running down each side that insert into corresponding holes in the circuit board. The part of the device that Nanopierce is addressing is the electrical connections between the die which is contained in that rectangular package and the package leads which extend to the outside of the package. In other words, how the signals get from the die, out of the package, and finally to the traces on the board.

The OLD way of doing this is by mechanical bonding. You bond very small wires from each bond pad on the die to it's corresponding pin on the package. The newer approach to this is "flip chip" technology, where each bond pad on the die is "bumped" (a material is deposited on each bond pad), then the die is flipped over and the connections are direct (no wires). This is NOT sub-micron work. Nanopierce's claim is that they have a better way to do the bumping process for flip chips (I don't know at this juncture if it is better or not, and am not trying to make that point.)

This paper from Nanopierce (Adobe PDF format) is a good explanation of what they are doing:

http://www.nanopierce.com/daten/technology/images_tec/pdfs/IMAPS_Zou_Neuhaus_FCAppl.pdf

Following is an excellent primer on the flip chip technology (generic, helps you understand what Nanopierce is trying to do). I have provided a snippet, but check out the whole section, it will really help you:

http://extra.ivf.se/ngl/B-Flip-Chip/ChapterB1.htm#B1

B1.1 Why flip-chip?

In the development of packaging of electronics the aim is to lower cost, increase the packaging density, improve the performance while still maintaining or even improving the reliability of the circuits. The concept of flip-chip process where the semiconductor chip is assembled face down onto circuit board is ideal for size considerations, because there is no extra area needed for contacting on the sides of the component. The performance in high frequency applications is superior to other interconnection methods, because the length of the connection path is minimised. Also reliability is better than with packaged components due to decreased number of connections. In flip-chip joining there is only one level of connections between the chip and the circuit board.

Potentially flip chip technology is cheaper than wire bonding because bonding of all connections takes place simultaneously whereas with wire bonding one bond is made at a time. In practise, however, this price benefit is not always achieved due to immature processes, e.g. the cost of die bumping with current processes can be significant, especially in low volumes.

Flip-chip joining is not a new technology. The technology has been driven by IBM for mainframe computer applications. Many millions of flip chips have been processed by IBM on ceramic substrates since the end of 60`s. At the beginning of 70`s the automotive industry also began to use flip chips on ceramics. Today flip-chips are widely used for watches, mobile phones, portable communicators, disk drives, hearing aids, LCD displays, automotive engine controllers as well as the main frame computers. The number of flip chips assembled was over 500 million in year 1995 and close to 600 million flip chips were consumed.

I hope this helps with your DD. Technology is a fast-moving entity. BTW, IBM has always been at the forefront of flip chip technology (they invented it). Your DD should also include research there, as they would be one of the major competitors.

Hope you don't mind this long-winded post. Just trying to help.

greg