Abstract: An electrical connector is for electrically connecting an electronic package with a circuit substrate. The connector includes a housing with a plurality of conductive terminals received therein, a fastening device for securing the electronic package. The fastening device includes a pressing member for pressing and securing the electronic package and a retaining member for securing the pressing member. At least one of the pressing member, the retaining member are produced from ferrite stainless steel material, and has a layer of high temperature resistant organic thin film thereon.

Abstract: A burn-in socket for receiving an IC package comprises a socket body, a plurality of contacts mounted in the socket body and an actuator movably mounted upon the socket body. Each contact in the socket body includes a pair of clipping arms with tip portions at free ends thereof respectively. Solder balls attached to the bottom of the IC package are respectively clipped between the pair of the tip portions and thus the IC package should be brought into electrical contact with the contacts of the burn-in socket. The tip portion is plated with a Pd—Co layer for reducing the attachment of the Sn and preventing the impedance of the contacts to increase. Meanwhile, the IC package can be sucked up successfully without absorption from the contacts of the burn-in socket.

Abstract: A solder ball is adapted for a ball grid array socket and comprises a core portion (1) and a layer (2) of solder alloy coated an outer surface of the core portion. The core portion is consisting of tin essentially, and the layer of solder alloy contains at least two metal materials.

Abstract: An electrical connector in accordance with a preferred embodiment comprises an insulative housing (2), a plurality terminals (3) received in the housing (2), and the housing (2) comprises two pair of sidewalls and defines a layer of metal films (222) around outer surfaces of at least a pair of opposite sidewalls (22) thereof which can prevent disturbance of the electromagnetic waves produced by other components, hence a steady electrical connection between the electrical connector and printed circuit board can be achieved.

Abstract: A diamine which is useful in preparing a new flexible polyamide and polyimide with an aromatic dicarboxylic acid and a tetracarboxylic dianhydrides, respectively, has a general formula as follows: ##STR1## wherein R.sub.1 is methyl (--CH.sub.3) and n is an integer ranging from 1 to 4.

Abstract: The new diamine, "3,3',5,5'-tetramethyl-2,2-bis[4-(4-amino-phenoxy)phenyl]propane" was synthesized and used to prepare high performance soluble engineering plastics by polycondensation. The polymer can be polyamides, polyimides or poly(amide-imide)s. These polymers exhibit excellent solubility, processability, heat resistance and mechanical performance.

Abstract: A new diamine, 2,2'-dimethyl-4,4'-bis(4-aminophenoxy)-biphenyl was synthesized and used to prepare high performance engineering plastics by polycondensation. The new diamine as shown in the following formula has a noncoplanar 2,2'-disubstituted biphenylene and a flexible aryl units: ##STR1## The engineering plastics disclosed in the present invention includes polyamides, polyimides and poly(amide-imide)s.

Abstract: A diamine which is useful in preparing a new flexible polyamide and polyimide with an aromatic dicarboxylic acid and a tetracarboxylic dianhydrides, respectively, has a general formula as follows: ##STR1## wherein R.sub.1 is a proton (--H) or methyl (--CH.sub.3) and n is an integer ranging from 1 to 4. These polyamide and polyimide exhibit good mechanical performance and processability.