Manufacturing & Prototyping

Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10–50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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New Thermal Management Strategies for Medical Devices

Heat pipes and vapor chambers are being utilized to address challenging thermal management requirements. In an increasing number of medical device applications, thermal issues limit the overall performance and reliability of the system. Basic thermal management strategies such as liquid cold plates, air cooled heat sinks, and thermal interface materials are becoming insufficient as stand-alone solutions. In many new medical applications, implementation of advanced thermal technologies such as heat pipes and vapor chambers are becoming an integral part of the thermal management solution. These technologies offer excellent heat transfer and heat spreading performance. Furthermore, they are passive (no energy, no moving parts), quiet, and reliable. Several medical devices, such as powered surgical forceps, skin/tissue contacting devices, and polymerase chain reaction (PCR)/thermocyclers already use these technologies, and more applications are emerging. A discussion of heat pipe and vapor chamber operation and selected medical device applications follows.

Posted in: Bio-Medical, Thermal Management, Manufacturing & Prototyping, Medical, Briefs, MDB

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Guidelines for Thermoplastic Color Control and Change Management

In order to make good color specifications, the OEM should gain an understanding of color technology, color measurement, and methods available to control color. Color is an important factor in many aspects of medical devices, from design to how the device is used and by whom. In 2010, the FDA and regulatory bodies around the world increased their scrutiny of colors as additives in all materials and are paying special attention to the biologic testing performed on pigments used in plastic in an effort to reduce potential safety risks.

Posted in: Bio-Medical, Manufacturing & Prototyping, Plastics, FDA Compliance/Regulatory Affairs, Medical, Briefs, MDB

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SFDC/DHR Interface Systems Add Parametric Data to Support Medical Manufacturers

Access to parametric data allows OEMs to monitor device performance throughout production, and is particularly useful for new product introduction. In this era of ever more stringent FDA oversight and regulations, the responsibility for vigilance falls on medical manufacturers and their manufacturing partners or customers. Those companies that support a “best practices” medical manufacturing environment often rely on a shop floor data collection (SFDC) system that embeds attributive data in each unit’s device history record (DHR). More recent advances allow for parametric, or performance, data to be captured as well, so that not only can the medical device’s progress through the manufacturing process be monitored, the device’s quality of performance at each stage can also be assessed. Access to this data facilitates timely decision- making, ensuring the highest quality medical product, and saving money due to reduced downtime, scrap and/or repair work.

Posted in: Bio-Medical, Manufacturing & Prototyping, FDA Compliance/Regulatory Affairs, Medical, Data Acquisition, Briefs, MDB

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Carbon Nanotube Bonding Strength Enhancement Using Metal “Wicking” Process

Carbon nanotubes grown from a surface typically have poor bonding strength at the interface. A process has been developed for adding a metal coat to the surface of carbon nanotubes (CNTs) through a “wicking” process, which could lead to an enhanced bonding strength at the interface. This process involves merging CNTs with indium as a bump-bonding enhancement.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Germanium Lift-Off Masks for Thin Metal Film Patterning

This innovation has uses in the fabrication of transition edge sensors and microwave kinetic inductance detectors. A technique has been developed for patterning thin metallic films that are, in turn, used to fabricate microelectronics circuitry and thin-film sensors. The technique uses germanium thin films as lift-off masks. This requires development of a technique to strip or undercut the germanium chemically without affecting the deposited metal. Unlike in the case of conventional polymeric lift-off masks, the substrate can be exposed to very high temperatures during processing (sputter deposition). The reason why polymeric liftoff masks cannot be exposed to very high temperatures (>100 °C) is because (a) they can become cross linked, making lift-off very difficult if not impossible, and (b) they can outgas nitrogen and oxygen, which then can react with the metal being deposited. Consequently, this innovation is expected to find use in the fabrication of transition edge sensors and microwave kinetic inductance detectors, which use thin superconducting films deposited at high temperature as their sensing elements.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Multi-Layer Far- Infrared Component Technology

A method has been developed for fabricating high-reflectivity, multi-layer optical films for the terahertz wavelength region. A silicon mirror with 99.997-percent reflectivity at 70 μm wavelength requires an air gap of 17.50 μm, and a silicon thickness of 5.12 μm. This approach obtains pre-thinned wafers of about 20 mm thickness in order to measure their thickness precisely. A gold annulus of appropriate thickness is deposited to reach the required total thickness. This, in turn, has the central aperture etched down to the desired final silicon thickness. Also, the novel Bragg stack optics in this innovation are key to providing Fabry-Perot spectroscopy and improved spectral component technologies of unprecedented resolution, free spectral range, and aperture.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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