Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microtechnology: An alignment assignment

21.01.2011
Photonics and microelectromechanical systems fabricated separately on different wafers can now be aligned precisely by finishing with a single processing step

Microelectromechanical systems (MEMS), which consist of tiny moving parts driven by electrical signals, have found ready applications in optical communication systems. They are attractive in part because they can be integrated with other electrical and optical components to create a multifunctional device in a single package, which reduces fabrication costs and allows for greater performance. However, this integration requires precise alignment of the constituent parts in order to avoid signal loss.

One approach to achieve accurate alignment is to manufacture both the optical MEMS components and any other electronic or photonic components on the same silicon wafer. Optical MEMS devices, however, are often ten times thicker than other optical components. This means that different fabrication techniques are needed for the different components, making alignment difficult.

Another approach is to fabricate MEMS and electrical components on two separate wafers that are then bonded together. Achieving good alignment in this scheme is made difficult, however, by the coarse bonding processes that are available. Qingxin Zhang and co-workers at the A*STAR Institute of Microelectronics[1] have now refined the two-wafer approach by combining the final fabrication step for each component into a single process.

The research team aligned an optical MEMS structure with a silicon photonic structure (see figure). The two wafers bearing the respective components were processed independently in the first step: the MEMS structure was fabricated on a bulk silicon wafer and the photonic structure on a silicon-on-insulator wafer. The wafers were then bonded together using benzocyclobutene—a commonly used bonding agent for MEMS—at 250 °C, and the two structures were completed simultaneously using a single step of deep reactive ion etching.

The use of a single fabrication step to complete the final integrated device allowed Zhang and his co-workers to meet strict alignment specifications, achieving a misalignment of less than one micrometer laterally and less than half a micrometer vertically. They also used their strategy to construct and characterize a functioning optical switch in which a MEMS mirror is displaced by a driving voltage to connect and disconnect an optical pathway. The signal loss between a source optical fiber and the silicon waveguide in the device was just 2.4 decibels, which is well within acceptable limits.

The new approach allows scientists to merge photonic and MEMS components fabricated on two different wafers into a single device. Future work will focus on optimizing the MEMS design and fabrication process, and demonstrating reconfigurability.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics

Journal information

[1] Zhang, Q. et al. A two-wafer approach for integration of optical MEMS and photonics on silicon substrate. IEEE Photonics Technology Letters 22, 269–271 (2010).

Lee Swee Heng | Research Asia Research News
Further information:
http://www.research.a-star.edu.sg/research/6267

More articles from Physics and Astronomy:

nachricht First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>