Chemical resistance of optical plastics and resin for level detectors

2015 ◽  
Author(s):  
Cicero L. Omegna ◽  
Jonas Fontes Garcia ◽  
Roddy E. Ramos-Gonzáles ◽  
Luiz C. Barbosa
Keyword(s):  
Chemical Resistance ◽  
Optical Plastics

Surface Modification of Poly (alkyl/Arylphosphazene) Thin Films

2000 ◽  
Vol 629 ◽  
Author(s):  
John V. St. John ◽  
Patty Wisian-Neilson
Keyword(s):  
Thin Films ◽  
Surface Modification ◽  
Chemical Resistance ◽  
Chemical Properties ◽  
Inorganic Polymers ◽  
Thin Polymer Films ◽  
Hydrophilic Interactions ◽  
Carboxylic Acid Groups ◽  
Polymer Interface ◽  
Thin Polymer

ABSTRACTPoly (methylphenylphosphazene) (PMPP) is an example of a unique class of inorganic polymers with alternating – (P=N)– backbones. Chemical modification of bulk PMPP can result in changes of physical properties such as chemical resistance, onset temperature of thermal degradation, elasticity, and flexibility. Surface modification of PMPP allows tailoring of the chemical properties at the polymer interface while maintaining the integrity of the bulk polymer. In this research, PMPP thin films were treated to form carboxylate or carboxylic acid groups at the surface. Surface modification was monitored by following changes in contact angle. The hydrophobic/hydrophilic interactions of carboxylated PMPP surfaces allow for mesoscale interactions of thin polymer films.

Backside Mechanical Preparation Methodology for Effective Failure Analysis on Small and Non-Exposed Die Paddle Package

2018 ◽  
Author(s):  
Ong Pei Hoon ◽  
Ng Kiong Kay ◽  
Gwee Hoon Yen
Keyword(s):  
Failure Analysis ◽  
Chemical Etching ◽  
Chemical Resistance ◽  
Etching Time ◽  
Lead Frame ◽  
Front Side ◽  
Electrical Measurements ◽  
Mechanical Preparation ◽  
Die Surface ◽  
Copper Lead

Abstract Chemical etching is commonly used in exposing the die surface from die front-side and die backside because of its quick etching time, burr-free and stress-free. However, this technique is risky when performing copper lead frame etching during backside preparation on small and non-exposed die paddle package. The drawback of this technique is that the copper leads will be over etched by 65% Acid Nitric Fuming even though the device’s leads are protected by chemical resistance tape. Consequently, the device is not able to proceed to any other further electrical measurements. Therefore, we introduced mechanical preparation as an alternative solution to replace the existing procedure. With the new method, we are able to ensure the copper leads are intact for the electrical measurements to improve the effectiveness and accuracy of physical failure analysis.

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