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Matt Wiens


A)Chips Go Vertical


B) John Baliga (27 February, 2004). Chips Go Vertical.   Spectrum Online, Weekly Feature. Retrieved March 11, 2004, from


C) Introduction


The ever-increasing technology in microchip design is now forcing chip engineers to become more creative when creating new chips.  The performance of the wires connecting the transistors has become the limiting factor for microchip performance instead of the number of transistors on the chips.  To overcome the inherent obstacles of placing so many transistors and wires together the newest wave of chip design is to stack the individual chips to make three-dimensional integrated circuits.  The article discusses some front-running design techniques and the companies using them.

D) Analysis          

Since the 1960ís the development of microchip technology has been screaming along at an impressive pace.  We have gone from computers the size of buildings to computers that fit in the palm of your hand.  In recent years the number of transistors on one chip has reached 410 million and will soon be at 1 billion.  This has caused the recent design problems to be the wires connecting the transistors (as thin as 90 nanometers) to reach combined lengths of 7 kilometers per square centimeter.  Combine this wire length with the capacitance added by the insulation on the wires and it all adds up to unwanted power consumption and heat production.  There are three basic strategies for handling this problem: three-dimensional chips, X Architecture (using 45-degree angles to connect transistors) and the network on a chip approach (see article for explanation). 

                The three-dimensional approach stacks multiple dies with direct connections tunneling through them.  This reduces interconnect lengths and increases the number of transistors within one cycle of each other.  There are several different ways to produce the three-dimensional chip and several different companies are starting to fund the various programs working on this technology.  Tru-Si Technologies of Sunnyvale, California is being funded by Intel and Ziptronix Inc is being funded by Xilinx for example.  Each company has its own development philosophies and the article discusses many different ways that chip stacking could be addressed and some philosophical ideas behind them which I donít think helped the article very much.

                The article concludes by saying that cost and yield will decide whether these new chip designs ever make it to the market which I feel is a pretty basic understanding of how corporations work and was just a cheap way to end an article.

                Overall, the article is very detailed as I would expect from Spectrum Online which is for technically savvy readers.  I do believe that in the middle of the article he deviates from the topic for a paragraph when he starts talking about pixel arrays and infrared heat sensing and chemical detection.   The article gives nice historical background and covers the topic very thoroughly without taking sides as to whether this technology will succeed or fail.