Copper, gold and tin for efficient chips

December 6, 2012
This photo shows an employee at the MST Lab & Fab, where the post processing of chips takes place. Credit: Fraunhofer IMS

With gold, copper or tin and special galvanizing processes, scientists are improving the function of semi-conductors and making the manufacture of microelectronic systems a child's play. Especially the LED industry could profit from this.

They are particularly small, durable and economical: LEDs have conquered the ; it is already possible today to recognize the make of a car by the design of the LED headlights. Whether in the interior, displays, infotainment system or brake lights, parking lights or fog lights – a modern car offers many possibilities for LED technology to be used for lighting. Unlike the traditional halogen or xenon lights, need LED drivers. Their most important task: they must continuously supply the light diodes with power. In addition, they are to carry out complex tasks and to control, for example, several in series, or switch individual ones on in multiple stages if the is to be dimmable.

The requirements relating to the drivers are enormous: they must be immune to the high temperature and voltage differences in a car or be resistant to . In order to guarantee reliable , a higher voltage must flow through the circuits of the LED drivers. Researchers from the Fraunhofer Institute for and Systems IMS offer manufacturers a process to manufacture the chips that suit these applications: it is based on galvanization, a process in the , in which special metals are deposited on the semiconductors.

Copper for increased current flow

However, Prof. Holger Vogt's department at the IMS, is backing copper, in particular. "This way, we can have more current flow through the chips", explains Vogt. That is important, because for most applications the chips must become smaller and smaller – the current that flows through them, however, stays the same. However, integrating , such as a layer of copper, is not always without problems, since there are limits to the regular processes for manufacturing chips. It is for this reason that the scientists at the IMS specifically constructed a manufacturing line for "post processing" – the MST Lab & Fab – to be able to subsequently improve the chips on the substrate wafers, depending on the requirements of the application.

In addition to copper, the engineers are also able to deposit other metals or compounds such as copper-tin or gold-tin onto the chips. "These layers can be soldered", explains Vogt. That offers a substantial advantage: the cover can be soldered onto the , right there on the wafer. "The result is the smallest housing for a chip that can be had", says Vogt. It can be used to surround and protect sensitive sensors without negatively affecting their functionality. One example is bolometers, sensors that are used to measure temperature. Because the housings for bolometers must additionally also be put into a vacuum environment to provide accurate measurements, their manufacture to date has been very complex and thus expensive. However, with the help of the MST Lab & Fab, housings that are cost-effective and therefore suitable for mass production can be manufactured.

In addition, the researchers in the MST Lab & Fab have been able to construct complex components within a single housing. The are able to solder two chips, such as an opto-chip with highly sensitive photo sensors with a CMOS-Chip (Complementary Metal Oxide Semiconductor) which can measure individual photons, to each other, using the copper galvanization process. Such microelectronic components are suitable for night-vision devices or for low-light microscope applications.

Explore further: Color sensors for better vision

Related Stories

Color sensors for better vision

October 5, 2009

CMOS image sensors in special cameras -- as used for driver assistance systems -- mostly only provide monochrome images and have a limited sensitivity to light. Thanks to a new production process these sensors can now distinguish ...

UV-transparent coating for image sensors

February 8, 2011

Image sensors as used in cell phones are partially color-blind. This is because of their coating, which prevents UV light from passing through. CMOS chips have as a result not been suitable for spectroscopy up to now. A new ...

The fine art of etching

June 8, 2011

( -- They see more than the naked eye and could make traffic safer: miniaturized thermal imaging sensors. But they are difficult to manufacture on a commercial scale. Researchers have now developed a new system. ...

High-speed CMOS sensors provide better images

January 3, 2012

Conventional CMOS image sensors are not suitable for low-light applications such as fluorescence, since large pixels arranged in a matrix do not support high readout speeds. A new optoelectronic component speeds up this process. ...

LEDs on silicon can reduce production costs

May 21, 2012

A new manufacturing technology is expected to greatly reduce the cost of light-emitting diodes (LEDs) in the future. For the first time ever, researchers at the Siemens subsidiary Osram Opto Semiconductors were able to successfully ...

Recommended for you

Drone market to hit $10 billion by 2024: experts

October 3, 2015

The market for military drones is expected to almost double by 2024 to beyond $10 billion (8.9 billion euros), according to a report published Friday by specialist defence publication IHS Jane's Intelligence Review.

Radio frequency 'harvesting' tech unveiled in UK

September 30, 2015

An energy harvesting technology that its developers say will be able to turn ambient radio frequency waves into usable electricity to charge low power devices was unveiled in London on Wednesday.

Professors say US has fallen behind on offshore wind power

September 29, 2015

University of Delaware faculty from the College of Earth, Ocean, and Environment (CEOE), the College of Engineering and the Alfred Lerner School of Business and Economics say that the U.S. has fallen behind in offshore wind ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

3 / 5 (2) Dec 06, 2012
What exacty is new about this? Gold and copper has been used in chips since the 70s and the CPU in the computer you are using has gold in it!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.