Uncooled micromachined bolometer arrays on flexible substrates

This paper reports progress on the development of micromachined infrared microsensors on flexible polymer substrates. The flexible substrates were formed by spin-coating polyimide films (HD Microsystems PI-5878G) on silicon wafer carriers. Semiconducting Yttrium Barium Copper Oxide (YBCO) was used as the thermistor. The microbolometer was fabricated using a polyimide (HD Microsystems PI2737) sacrificial mesa and titanium electrode arms. The YBCO thermistor was suspended above the substrate by the electrode arms after the sacrificial layers have been removed by micromachining. The polyimide substrate was then removed from the silicon wafer carrier to complete the fabrication of the infrared microsensors on a flexible polyimide substrate. The measured thermal conductance of the microbolometers ranged from 9.07 x 10-6 W/K for a non-micromachined to 4.0 x 10-7 W/K for a micromachined sensor. As a result, the responsivity and detectivity were measured to be as high as 6.1 x 104V/W and a 1.2 x 108 cmHz1/2/W, respectively, with a 970 nA current bias. This level of performance is comparable to similar miromachined detectors fabricated on silicon substrates.

[1]  Yong Xu,et al.  IC-integrated flexible shear-stress sensor skin , 2003 .

[2]  Thomas N. Jackson,et al.  Pentacene organic thin-film transistors for circuit and display applications , 1999 .

[3]  Mahmoud Almasri,et al.  Self-supporting uncooled infrared microbolometers with low-thermal mass , 2001 .

[4]  Chih-Ming Ho,et al.  A flexible MEMS technology and its first application to shear stress sensor skin , 1997, Proceedings IEEE The Tenth Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots.

[5]  Donald P. Butler,et al.  MgO sacrificial layer for micromachining uncooled Y-Ba-Cu-O IR microbolometers on Si/sub 3/N/sub 4/ bridges , 1999 .

[6]  Donald P. Butler,et al.  A semiconductor YBaCuO microbolometer for room temperature IR imaging , 1997 .

[7]  J. Gardner,et al.  Microsensors: Principles and Applications , 1994 .

[8]  Z. Celik-Butler,et al.  Microbolometers on a flexible substrate for infrared detection , 2004, IEEE Sensors Journal.

[9]  Donald P. Butler,et al.  Uncooled infrared microbolometers on a flexible substrate , 2002 .

[10]  E. Dereniak,et al.  Infrared Detectors and Systems , 1996 .

[11]  David J. Beebe,et al.  A flexible polyimide-based package for silicon sensors , 1994 .

[12]  Z. Çelik-Butler,et al.  Fabrication of semiconducting YBaCuO surface-micromachined bolometer arrays , 1997 .

[13]  Paul W. Kruse,et al.  A comparison of the limits to the performance of thermal and photon detector imaging arrays , 1995 .