Reliability aspects of a radiation detector fabricated by post-processing a standard CMOS chip

Salm, Cora; Carballo, V.M. Blanco; Melai, J.; Schmitz, Jurriaan

doi:10.1016/j.microrel.2008.06.038

Cited by 10 publications

(12 citation statements)

References 12 publications

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“…Because the layer thicknesses were all found to be as expected (in accordance with known spin-curves) the starting material must be comparable in all cases. e variation in nal solvent concentration might be due to environmental conditions, similar to the results on SU-8 adhesion presented in [79]. e variation .…”

Section: Gc-ms Measurementssupporting

confidence: 79%

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Photon imaging using post-processed CMOS chips

Melai¹

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Section: Gc-ms Measurementssupporting

confidence: 79%

“…I may seep into the layers and deteriorate the layer quality and performance. After development a nal Hard-Bake (HB) step may be given to strengthen the layer, remove small cracks and improve adhesion [78,79]. is is normally done on a hotplate at temperatures between 120 and 180 • C [71].…”

Section: Standard Su-8 Processmentioning

confidence: 99%

Photon imaging using post-processed CMOS chips

Melai¹

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“…Recently, KMPR (MicroChem Corp) has emerged as a new photopolymer alternative with photolithography characteristics similar to those of SU-8 [12]. But unlike SU-8, KMPR is less susceptible to cracking during lithography [13] and has excellent adhesion to metals [13][14][15]. If KMPR and SU-8 are deposited on Al/Cu, and then left in a moist environment, SU-8 loses adhesion quickly, while KMPR maintains a strong adhesion, even for several days [14].…”

Section: Introductionmentioning

confidence: 99%

Multilayer bonding using a conformal adsorbate film (CAF) for the fabrication of 3D monolithic microfluidic devices in photopolymer

Gutierrez-Rivera¹,

Martinez-Quijada²,

Johnstone³

et al. 2012

J. Micromech. Microeng.

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Reliable microfabrication processes and materials compatible with complementary metal-oxide semiconductor (CMOS) technology are required by industry for the mass production of complex and highly miniaturized lab-on-a-chip systems. Photopolymers are commonly used in the semiconductor industry, and are suitable for the integration of multilayer structures onto CMOS substrates. This paper describes a novel photopolymer bonding process compatible with CMOS technology for the fabrication of three-dimensional monolithic microfluidic devices. The process consists of the formation of a conformal adsorbate film (CAF) approximately 15 nm thick on a patterned photopolymer layer (KMPR), thereby increasing the number of open polymer chains at the bonding interface and acting as an ultra-thin adhesive layer. This thin adhesive layer is made of the same photopolymer as the microfluidic structures, but has a substantially lower crosslinking density so it will be able to make better bonds during a thermocompressive bonding step. This CAF treatment substantially improves the bonding yield between two patterned and previously crosslinked photopolymer layers because both optimum structure strength (to resist deformation during bonding) and bonding strength from epoxy crosslinking can be achieved. We demonstrate high bonding yields of up to 99% of the useful area of the substrate after three successive bonding steps. With this technique, up to six layers have been bonded in a single device. Unlike previously reported methods the quality of bonding is mostly decoupled from soft-bake parameters and crosslinking level of the previously patterned layers. Three different bonding processes were characterized to describe the bonding mechanism and the differences between the presented method and the partial-crosslinking bonding method. Capillary filling experiments were performed in microchannels of multilayer structures built with the CAF technique, without any observable leakage between layers.

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“…KMPR has also been shown to have an increased moisture resistance compared to SU-8 [5], demonstrating stable adhesion to substrates when exposed to humid conditions for several days. From a processing point of view, KMPR may be spun up to 100 μm thick in a single spin, displays better adhesion to substrates than SU-8 [6,7], requires less stringent baking conditions to avoid cracking than SU-8 [3] and has high chemical, plasma and dry etch resistance [8]. As a structural material KMPR has been shown to facilitate bonding between layers while maintaining good sidewall profiles [9].…”

Section: Introductionmentioning

confidence: 99%

“…KMPR has seen use in a number of areas such as microfluidic structures [9], RIE masking layers [8,10], electrodeposition molds [11][12][13][14], proton beam writing [15], absorbance filters for microfluidics (when mixed with appropriate dyes) [16] and structural materials in radiation imaging detection [6].…”

Section: Introductionmentioning

confidence: 99%

Variation of thermal and mechanical properties of KMPR due to processing parameters

Reynolds

Elias

Elliott

et al. 2012

J. Micromech. Microeng.

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We present a study of the thermal and mechanical properties of the negative photoresist KMPR and the influence of processing conditions on those properties. The process parameters chosen all relate to the cross-linking level of the photoresist: the UV exposure dose, the baking temperature and the bake length. The stability of KMPR at high temperatures was also examined. The glass transition temperature was measured using dynamic mechanical analysis, with a maximum measured value of 128 • C achieved in our tests. Relating the glass transition temperature to the cross-linking level of the material, exposure doses higher than 2 J cm −2 were shown to have a negligible effect on the cross-linking (for 80 μm thick films). Using thermogravitmetric analysis, KMPR has been shown to lose significant mass when heated above 200 • C. Young's modulus of KMPR was measured to be between 2.0 GPa for samples hard-baked at 100 • C and 2.7 GPa for samples baked at 150 and 200 • C. Creep behavior for KMPR held under strain was studied for samples prepared under a range of processing temperatures. Finally the thermally-induced cross-linking of unexposed KMPR was studied, with samples post-exposure baked at 150 • C, or 120 • C for at least an hour, cross-linking sufficiently to prevent development.

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Reliability aspects of a radiation detector fabricated by post-processing a standard CMOS chip

Cited by 10 publications

References 12 publications

Photon imaging using post-processed CMOS chips

Photon imaging using post-processed CMOS chips

Multilayer bonding using a conformal adsorbate film (CAF) for the fabrication of 3D monolithic microfluidic devices in photopolymer

Variation of thermal and mechanical properties of KMPR due to processing parameters

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