We begin with the following observation. The price of most of the things increases every year.  Whether it is petrol, or food, or land, or gold, the price usually increases with time. However, a remarkable exception to this trend is the price of electronic goods.  The price of a computer or cell phone decreases every year. In addition, the power and functionality of these items becomes more.  In fact, some of the ‘old models’ are no longer available and are superseded by new, more powerful and less expensive models. Why do electronic goods show a different trend compared to all other goods?

At the heart of the electronic goods is microelectronic chip or integrated chip (IC). Every year, there is significant advancement in the technology of making these chips. Because of the advancements, the power of the chip increases while the production cost decreases. That is the reason for the decrease in cost of the electronic goods over time.

In this course, we will learn the process steps used in making the IC.  First, we will see a brief history of ICs.  In 1947, William Shockley, John Bardeen and Walter Brattain invented a device called transistor. It is somewhat like a switch, in the sense it can be turned ‘on’ or ‘off’. Before the invention of transistors, electrical circuits consisting of resistances, capacitances and triodes (using vacuum tubes) were used in making radios and televisions. They were bulky, expensive and used a lot of electricity. In the beginning, the transistors were made separately and were connected using wires.   In this method, it was not possible to make many circuits. Then in 1957, Jack Kilby created five transistors simultaneously and formed a circuit. Since all the transistors of the circuits are created simultaneously, this is called ‘integrated chip’. The difference between creating the transistors separately and creating them together can be illustrated with the following analogy. If we use a type writer to write a letter, then each letter has to be typed one by one. If we want to make 10 such letters, then it takes a long time to do that in the typewriter. On the other hand, in a printing press, all the letters of a page are arranged. The initial preparation takes some time. But once the letter is ready, making 10 or more copies is fast. Similarly, making transistors one by one is relatively simple, but time consuming task. Making all the transistors together is a bit more complex process, but when many such replicas are produced, it saves a lot of time. After Jack Kilby, Rober Noyce improved the manufacturing process. Now, many millions of transistors are routinely created in a single integrated chip.