60 years ago
The very first Integrated Circuit by Jack Kilby
Big bang of microelectronics: The first Integrated Circuit
Old and current inventions around the production of microchips
Just in time for the end of the summer holidays in Bavaria, here comes the story of an engineer who was not allowed to take a vacation - and who made a groundbreaking invention during this time. Jack Kilby had just started work at Texas Instruments in Dallas in the summer of 1958 and was therefore banned from taking holidays. While his colleagues were all away on vacation, the lonely Kilby made good use of the time in the empty laboratory. When his team returned from the holidays, Kilby presented them with a milestone in the history of technology on September 12, 1958: the first integrated circuit, practically the progenitor of the microchip.
A decisive breakthrough towards microelectronics had taken place a few years earlier with the invention of the transistor: In 1947, John Bardeen, William Shockley and Walter Houser Brattain developed the bipolar transistor at Bell Laboratories - still the cornerstone of all microelectronics today. Together, they received the Nobel Prize for this in 1956. Important steps in this direction had already been taken earlier (Julius Edgar Lilienfeld recieved the first patent for the transistor principle in 1925), but they were not ready for practical use.
Breakthrough with semiconductors
The transistor could now replace the large, heavy electronic valves, but since a lot of transistors were needed for more complex computational tasks and these had to be wired in a complex way, the problem was still that a lot of space and material was needed for the calculating machines.
This problem was solved by Jack St. Clair Kilby from Great Bend, Kansas (1923-2005). He combined transistor, resistor and capacitor on a common component. The decisive factor with the Integrated Circuit (IC) is the fact that the components are mounted on a plate, which is itself a component of the circuit. The semiconductor material (Kilby used germanium, today silicon is most common) saves cabling and makes it possible to accommodate a large number of transistors in a very small space.
Kilby's circuit was a so-called "flip-flop" or "bistable multivibrator". Such one-bit memories are still the basic element of any computer memory today.
The first one to register takes the prize
"Miniaturized electronic circuits": drawing from Kilby´s US 3138743
The story of Kilby and the IC is also a lesson that shows once again how important it is to quickly register and protect your intellectual property. At the same time and independently of Kilby, Robert Noyce had also developed the integrated circuit( US 2981877A). Noyce worked for Fairchild Semiconductors, who had just developed the first diffusion bipolar transistor. Noyce was even one step ahead of Kilby and was already using photolithographic processes and diffusion processes to produce his IC. But Kilby was the first to apply for a patent for his development ( US 3138743 A).
There were years of patent disputes, but in retrospect Kilby and Noyce went down in history as equal inventors of the IC. When Kilby received the Nobel Prize in Physics in 2000, he was certain that he would have been awarded the prize together with Noyce had he been alive: "While Robert and I followed our own paths, we worked hard together to achieve commercial acceptance for integrated circuits. If he were still living, I have no doubt we would have shared this prize." Noyce, co-founder of Intel and early investor of AMD, had already died in 1990.
Rapid development deep into the nano range
"Semiconductur device-and-lead structure": drawing from Robert Noyce´s US 2981877 A
In 1958, however, it took some time for the IC and the first microprocessors to establish themselves on the market. A milestone was the first pocket calculator presented by Texas Instruments in 1966, in whose development Kilby played a major role. Kilby is also regarded as the father of the thermal printer.
The integrated circuit is still the basic element of digital technology today, whether in kitchen appliances, smartphones, cars or computers. As Moore's Law predicted in 1965, the number of circuits that can be accommodated on a chip doubles every 18 months or so. Today, the microprocessor of a PC can contain several billion transistors.
But how can such an unimaginable number of circuits be accommodated on a small silicone plate? Semiconductor wafers prepared with photoresist are usually exposed in various steps using a photolithographic process. The complex structures of the microchip are applied. Today, these structures can be resolved into the single-digit nanometer range.
Photolithography and microchip
Drawing from DE 102015209173
The production of integrated circuits offers a wide field for inventor activities. An important method in the manufacturing process of microchips is photolithography. And an important detail of a lithography system are projection lenses in which optical elements are mounted or optical elements are connected to form a lens housing.
A standard projection lens, for example, has twenty lenses ( DE 10 2008 026 979 B3). The mass of a lens is between 1 and 10 kg (see e.g. DE 10 2004 014 641 A1). The resolution of the smallest structures down to below 9 nm, the very large and heavy projection lenses in comparison (see DE 10 2015 209 173 A1) as well as the energy input by absorption of light of the irradiated operating wavelength alone present challenges and problems for the projection lenses. For many years, inventors have been experimenting with the holders and mounts of the optical elements.
The size and weight ratios of the optical elements as well as the prevailing operating temperatures in a projection lens shall be taken into account in a lithography system. The storage and cooling of the optical elements as well as the thermal expansion and thermal conduction of the mount must be taken into account with regard to constant imaging conditions.
Current inventions dealing with this topic are presented in the article „Fassungen optischer Elemente in der Photolithographie“ , which was published in the latest edition of the "Erfinderaktivitäten". DPMA patent examiner Roland Deninger analyses the ideas applied for concerning the assembly of projection lenses, their mounting, damping, cooling or concepts for temperature compensation.
- If you would like to learn more, you can read the full article here (5,1 MB) in the latest "Erfinderaktivitäten" edition of (in German only).
Picture: Texas Instruments
Last updated: 25/03/19