Parylene <scp>AF</scp>‐4 via the Trapping of a Phenoxy Leaving Group

Senkevich, Jay J.

doi:10.1002/cvde.201304321

Cited by 5 publications

(5 citation statements)

References 16 publications

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“…For the deposition of thin film AF4 parylene coatings, vapor deposition polymerization (VDP) based on the Gorham process is used since it produces homogenous films and covers small holes and edges very well. The VDP process seen in Figure 1b needs solid dimers, which become sublimated over 100 • C. This vapor is then pyrolyzed over 600 • C and only fluorinated monomers are left for the final step, where the polymerization of AF4 takes place on the substrate material at room temperature [1,18,20,21]. Since parylene AF4 offers such outstanding properties, research was conducted on using it as a dielectric barrier coating for MEMS applications [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Assessment of AF4 Parylene Cohesion/Adhesion on Si and SiO2 Substrates by Means of Pull-Off Energy

2023

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Advanced packaging solutions require insulation and passivation materials with exceptional properties which can also fulfill the reliability needs of electronics devices such as MEMS, sensors or power modules. Since bonding (cohesive/adhesive) properties of packaging coatings are very important for reliable functioning of electronics devices, the bonding of aliphatic fluorinate-4 (AF4) parylene coatings was assessed in this work. As there is a lack of data regarding its bonding towards different substrates, pull-off tests of 1.6 and 2.5 µm thick AF4 coatings on silicon (Si) and glass (SiO2) substrates were performed. These showed a clear difference in the pull-off F/s curves between the AF4 coatings on Si and SiO2 substrates. This difference is parameterized by the pull-off energy, which will be presented in this work. To further understand the origin of the distinction in the pull-off energies between the AF4-Si and AF4-SiO2 samples and subsequently the cohesive/adhesive properties, mechanical and structural characterization was conducted on the AF4 coatings, where a clear difference in the E-modulus and crystallinity was observed. The Si and SiO2 wafers were shown to facilitate the CVD growth of the AF4 film distinctively, which likely relates to the divergent thermal properties of the substrates. Understanding of the cohesive/adhesive properties of AF4 coatings on different substrate materials advances the usage of the AF4 in electronics packaging technologies.

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Section: Introductionmentioning

confidence: 99%

Assessment of AF4 Parylene Cohesion/Adhesion on Si and SiO2 Substrates by Means of Pull-Off Energy

2023

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“…It is produced by chemical vapour deposition (CVD) via the Gorham method [4]. The problem though is a very high precursor cost [5,6]. Materials which are currently used as precursors are shown in figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…Octafluoro [2.2]paracyclophane (1), the precursor for parylene AF-4, is 75 times the cost of [2.2]paracyclophane, the precursor for parylene N, with a single-source supplier (Yuan-Shin Materials Technology Corp. Ltd, Kaohsiung, Taiwan). Although progress has been made, the difficulty with this synthesis is that it requires a total of three steps and the last one is not scalable and of low yield [6][7][8]. An alternative route to parylene AF-4 is to start with one of the intermediate synthetic products 1,4-bis(bromodifluoromethyl)benzene (2) as the CVD precursor [9].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it is desirable to have a scalable synthetic route to the parylene AF-4 precursor that circumvents the production of corrosive by-products during the cracking process. For detailed information about the CVD of parylene AF-4 with the diphenoxide-based precursor, please see the paper 'Parylene AF-4 via the Trapping of a Phenoxy Leaving Group' of Senkevich, which is available upon open access (Research Gate) [6]. In this paper, he proposed a three-step synthesis of 1,4-bis[difluoro(phenoxy)methyl]benzene (3) from diphenylterephthalate as the starting material, as is shown in figure 2.…”

Section: Introductionmentioning

confidence: 99%

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Improved route to a diphenoxide-based precursor for chemical vapour deposition of parylene AF-4

2021

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In this work, we present the synthesis of an alternative precursor for chemical vapour deposition of parylene AF-4 to the widely used standard, octafluoro[2.2]paracyclophane. The standard precursor suffers from uncertainties in its supply chain and its synthesis is of low yield. A comparison between different reaction parameters and solvents is drawn by means of thermal, laboratory-scale and microwave-assisted reactions and quantitative nuclear magnetic resonance (qNMR) studies.

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“…On Parylene VT‐4 instead, no works as electret material exist in the literature. Parylene AF‐4 and VT‐4 are highly compliant, MEMS‐compatible and present excellent thermal and dielectric properties with high dielectric strength, which make them potential candidates for energy harvesting applications …”

Section: Introductionmentioning

confidence: 99%

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

Lagomarsini

Jean‐Mistral

Kachroudi

et al. 2019

J of Applied Polymer Sci

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Parylene C is used in many applications due to its high properties but it remains a material with moderate performance as long as it is intended for use as an electret. Hence, the generally accepted idea, rightly so, in the scientific and industrial community not to necessarily select parylene (i.e., parylene C) for applications where the endurance of the electret is a strong criterion. Our study provided a new perspective on the performance of parylenes as electret. In this case, we will talk about fluorinated Parylenes of the VT‐4 type and especially AF‐4 variant. Their thermal stability is outstanding and a charge stability is almost total up to 100 °C. A 50% reduction in the charge is recorded at a temperature as high as of 220 °C (9 μm thick Parylene AF‐4), making it one of the most efficient polymer electrets to date. Negatively and positively charged Parylene AF‐4 electrets presented similar performance over long durations, which is out of ordinary for the commonly employed polymeric electrets. Finally, these fluorinated polymers are therefore particularly promising new candidates for applications in electret‐based converters for energy harvesting. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48790.

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Parylene AF‐4 via the Trapping of a Phenoxy Leaving Group

Cited by 5 publications

References 16 publications

Assessment of AF4 Parylene Cohesion/Adhesion on Si and SiO2 Substrates by Means of Pull-Off Energy

Assessment of AF4 Parylene Cohesion/Adhesion on Si and SiO2 Substrates by Means of Pull-Off Energy

Improved route to a diphenoxide-based precursor for chemical vapour deposition of parylene AF-4

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

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