Washable Coatings for Packaging Processes

2016 ◽  
Vol 2016 (1) ◽  
pp. 000094-000099
Author(s):  
Alex Brewer ◽  
Alex Laymon ◽  
John Moore
Keyword(s):  
Polyvinyl Alcohol ◽  
Thermal Resistance ◽  
Room Temperature ◽  
Solder Bump ◽  
Dielectric Coating ◽  
Cross Linking ◽  
Thermal Compression ◽  
Temporary Bonding ◽  
Heat Activation ◽  
Industry Needs

Abstract Many packaging processes require the protection of components while another application is conducted. This may include a planarizing coat over large topography while a deposition, bonding, or curing step is completed. Washable coatings are materials that protect the substrate during thermal or mechanical activities and are simply washed away using readily available and green products, such as water or detergent. Washable products are not new, an example includes laser washable coatings that remove debris from the heat activation zone (HAZ) during scribe and break processes. In such cases, thermal resistance is desired as high as possible. The chemistry of washable products includes polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) [1]. While these are excellent choices for consumer packaging (e.g. laundry packets, vitamins), they are best used in electronics for room temperature processing due to their cross-linking upon exposure to heat and metals. Alternatively, thermal resistant and washable products (e.g. DaeCoat™ 515) are available that provide protection to ≥300°C without the aid of mechanical tooling [2]. Planarizing coatings over metals can be thick (>300μm) as in cases where solder bump encapsulation is needed during dielectric coating and cure or when another die is thermal compression bonded. This approach has been demonstrated with washable temporary bonding adhesives in protecting C4 bumps while bonding micro-bumped die onto FPGA interposers [3]. Washable adhesives have been created for thermal and vacuum driven processing as EMI/RFI shielding in a PVD tool. Such coatings are applied to porous substrates, affixing die, processing, and removal by water washing [4]. Success in these and related temporary applications depend upon matching the chemistry of the washable coating with the process. Our experience in creating solutions for these and other industry needs will be discussed as well as the criteria for using temporary washable coatings.

ZoneBOND™ Thin Wafer Support Process for Wafer Bonding Applications

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001080-001094 ◽  
Author(s):  
Jeremy McCutcheon ◽  
Robert Brown ◽  
JoElle Dachsteiner
Keyword(s):  
Integrated Circuits ◽  
Wafer Bonding ◽  
Integrated Circuit ◽  
Room Temperature ◽  
Adhesive Bonding ◽  
Temperature Stability ◽  
Optoelectronic Device ◽  
Mems Devices ◽  
Thermal Compression ◽  
Temporary Bonding

Wafer-to-wafer bonding is widely used to support both the production of integrated circuits and MEMS devices. Bonding may be accomplished in a variety of ways including anodic, thermal compression, and adhesive bonding. The bond may be either permanent or temporary. Permanent wafer bonding is used to combine two materials together that remain together for the life of the device, for example, in the production of Si/GaAs wafer heterostructures for integration of an optoelectronic device into silicon integrated circuit technology. Temporary bonding is used to support the device wafer during certain processing steps, and then removed once the device wafer is completed. Currently, there are several temporary bonding processes being developed in industry. The leading technology utilizes some form of polymeric material to temporarily fasten or bond a rigid backing material, usually silicon or glass, to the device wafer for processing. The main issues associated with these techniques are temperature stability of the adhesive, removal from the support wafer, and cleaning the adhesive from the device wafer. The ideal process would require bonding at an acceptable temperature (usually less than 200°C), surviving through higher temperature processes, followed by debonding at lower temperature or even room temperature. In this paper, an alternative solution is reported that utilizes current thermoplastic adhesives and silicon support wafers coupled with a patented technology, developed by Brewer Science, Inc. Support wafers are bonded to device wafers at acceptable temperatures, mechanical integrity is maintained through semiconductor or MEMs processing, and the completely processed device wafer is then safely debonded from the support wafer at room temperature.

Washable Coatings for Packaging Practices

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001413-001454
Author(s):  
John Moore ◽  
Alex Brewer
Keyword(s):  
High Pressure ◽  
Thermal Resistance ◽  
Water Soluble ◽  
Metal Contact ◽  
Process Window ◽  
Thermal Processes ◽  
Cross Link ◽  
Solder Bumps ◽  
Heat Activation ◽  
Industry Needs

Many packaging processes require the protection of components while another application is conducted. This may include a planarizing coat over large topography while a deposition, bonding, or curing step is completed. Washable coatings are materials that protect the substrate during thermal or mechanical activities and are simply washed away using readily available and green products, such as water or detergent. Washable products are not new, an example includes laser washable coatings that remove debris from the heat activation zone (HAZ) during scribe and break processes. In such cases, thermal resistance is of coatings is preferred as high as possible. While many products used for such applications include polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP), such materials are not good choices for thermal resistance as they cross-link when exposed to temperature or to metals, leaving residue that is difficult or impossible to remove. While these are water soluble, they were designed for industrial and consumer packaging applications such as laundry packets, vitamins, or other non-thermal processes. Using thermal sensitive materials as PVA and PVP for laser processes creates a narrow process window that requires special washing tools that use high-pressure nozzels or heat. Alternatively, thermal resistant washable products are available that provide protection to 300°C or more, and upon being exposed to such conditions and metal contact, will simply rinse away without the aid of mechanical tooling.[1] Planarizing coatings commonly require thermal resistance, as they can be thick (>300um) and perform in encapsulating solder bumps while a dielectric or another die is solder attached and temperatures in excess of 250°C are needed. This has been proven in the case of protecting C4 bumps while bonding micro-bumped die onto FPGA interposers.[2] Bonding and curing is conducted with water or detergent washable UV-cured adhesive coatings. Similar coatings have been proven for EMI/RFI shielding where coatings are applied to porous substrates followed by temporarily affixing die to be processed in a PVD tool. When completed, the die are removed while the coating is washed away in a cleaner.[3] The success in these and related temporary applications depend upon the use of the proper washable coating. Our experience in creating solutions for these and other industry needs will be discussed as well as the criteria for using temporary washable coatings.

Preparation of Nano-Sized ZrO2 Powders by Polyvinyl Alcohol-Gel Method

2012 ◽  
Vol 508 ◽  
pp. 27-31
Author(s):  
Xiao Li Ji ◽  
Guo Min Li ◽  
Hao Wang ◽  
Wei Wei Wan
Keyword(s):  
Particle Size ◽  
Polyvinyl Alcohol ◽  
Room Temperature ◽  
Raw Materials ◽  
Cross Linking ◽  
Calcine Temperature ◽  
Tetragonal Crystal ◽  
The Stability ◽  
20 Nm ◽  
Uniform Particle Size

Nano-Sized ZrO2 Powders Were Synthesized from ZrOCl2•8H2O by Polyvinyl Alcohol-Gel Technology, Using Polyvinyl Alcohol (PVA) as a Monomer and Glutaraldehyde (GA) as a Cross-Linking Reagent. The Stability of the Gel Was Affected by Concentration of PVA and GA, Volume of ZrOCl2•8H2O. Moderate Strength of Gel Was Synthesized by Raw Materials of PVA (2%), ZrOCl2•8H2O (30~40 g) and GA (10ml). Nano-Sized ZrO2 Was Obtained Finally, with Uniform Particle Size and Good Dispersibility, and Size Was about 20 nm. Doped ZrO2 with Stabilized Tetragonal Crystal Was Obtained at Room Temperature. The Effect of Calcine Temperature on Phase Structure of ZrO2 Powders Has Been Investigated.

Kinetics of the Thermal Disappearance of Radicals Formed During the Radiolysis of Aspartic Acid

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihai Contineanu ◽  
iulia Contineanu ◽  
Ana Neacsu ◽  
Stefan Perisanu
Keyword(s):  
Thermal Resistance ◽  
Aspartic Acid ◽  
Room Temperature ◽  
Esr Spectra ◽  
Complex Mechanism ◽  
Radical Species ◽  
Mechanisms Of Formation ◽  
Kinetics Of

The radiolysis of the isomers L-, D- and DL- of the aspartic acid, in solid polycrystalline state, was investigated at room temperature. The analysis of their ESR spectra indicated the formation of at least two radicalic entities. The radical, identified as R3, resulting from the deamination of the acid, exhibits the highest concentration and thermal resistance. Possible mechanisms of formation of three radical species are suggested, based also on literature data. The kinetics of the disappearance of radical R3 indicated a complex mechanism. Three possible variants were suggested for this mechanism.

Thermal Resistance of Fly Ash Geopolymers with Alumina as Additive

2018 ◽  
Vol 281 ◽  
pp. 182-188
Author(s):  
Yong Sing Ng ◽  
Yun Ming Liew ◽  
Cheng Yong Heah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Thermal Resistance ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Strength Degradation ◽  
Alumina Addition ◽  
Higher Temperature ◽  
Temperature Exposure

The present work investigates the effect of alumina addition on the thermal resistance of fly ash geopolymers. Fly ash geopolymers were synthesised by mixing fly ash with activator solution (A mixture of 12M sodium hydroxide and sodium silicate) at fly ash/activator ratio of 2.5 and sodium silicate/sodium hydroxide ratio of 2.5. The alumina (0, 2 and 4 wt %) was added as an additive. The geopolymers were cured at room temperature for 24 hours and 60°C for another 24 hours. After 28 days, the geopolymers was heated to elevated temperature (200 - 1000°C). For unexposed geopolymers, the addition of 2 wt % of alumina increased the compressive strength of fly ash geopolymers while the strength decreased when the content increased to 4 wt.%. The temperature-exposed geopolymers showed enhancement of strength at 200°C regardless of the alumina content. The strength reduced at higher temperature exposure (> 200°C). Despite the strength degradation at elevated temperature, the strength attained was relatively high in the range of 13 - 45 MPa up to 1000°C which adequately for application as structural materials.

scholarly journals Transformation Between 2D and 3D Covalent Organic Frameworks via Reversible [2+2] Cycloaddition

2020 ◽  
Author(s):  
Thaksen Jadhav ◽  
Yuan Fang ◽  
Cheng-Hao Liu ◽  
Afshin Dadvand ◽  
Ehsan Hamzehpoor ◽  
...  
Keyword(s):  
Band Structure ◽  
Absorption Edge ◽  
Room Temperature ◽  
Three Dimensional ◽  
Cross Linking ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Doping Behavior ◽  
2D Polymers ◽  
2D And 3D

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2+2] cycloaddition cross-linking the π-stacked layers in 3D COFs. The reaction is reversible and heating to 200°C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-Vis absorption, altered luminescence, modified band structure and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant ion conductivity of 1.8×10<sup>−4</sup> S/cm and 3.5×10<sup>−5</sup> S/cm, respectively. Even higher room temperature proton conductivity of 1.7×10<sup>-2</sup> S/cm and 2.2×10<sup>-3</sup> S/cm was found for H<sub>2</sub>SO<sub>4</sub>-treated 2D and 3D COFs, respectively.

scholarly journals Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2867
Author(s):  
Myoung Jun Park ◽  
Grace M. Nisola ◽  
Dong Han Seo ◽  
Chen Wang ◽  
Sherub Phuntsho ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Self Assembly ◽  
Water Flux ◽  
Composite Membranes ◽  
Cross Linking ◽  
Support Surface ◽  
Eosin Y ◽  
Selective Layer ◽  
Assembly Technique

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

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