Improved conductive polymer device and method for manufacturing same

Abstract

An electronic device has three conductive polymer layers sandwiched between two external electrodes and two internal electrodes. The electrodes are staggered to create a first set of electrodes, in contact with a first terminal, alternating with a second set of electrodes in contact with a second terminal. The device is manufactured by: (1) providing (a) a first laminated substructure comprising a first polymer layer between first and second metal layers, (b) a second polymer layer, and (c) a second laminated substructure comprising a third polymer layer between third and fourth metal layers; (2) isolating selected areas of the second and third metal layers to form, respectively, first and second arrays of internal metal strips; (3) laminating the first and second laminated substructures to opposite surfaces of the second conductive polymer layer to form a laminated structure; (4) isolating selected areas of the first and fourth metal layers to form, respectively, first and second arrays of external metal strips; (5) forming insulation areas on the exterior surfaces of the external metal strips; and (6) forming a plurality of first terminals, each electrically connecting a metal strip in the first internal array to a metal strip in the second external array, and a plurality of second terminals, each electrically connecting a metal strip in the first external array to a metal strip in the second internal array; and (7) singulating the laminated structure into a plurality of devices, each having three polymer layers connected in parallel between first and second terminals.

Description

[0001] Cross References to Related Applications [0002] This application is a continuation-in-part of pending application No. 09 / 035,196 filed March 5,1998. Background technique [0003] The present invention relates generally to the field of conducting polymer positive temperature coefficient (PTC) devices, and more particularly to conducting polymer PTC devices of layered structure, having more than one layer of conducting polymer PTC material, especially formed into a shape suitable for surface mounting. [0004] Electronic devices containing elements made of conductive polymers have become increasingly common in various applications, for example, they are widely used in overcurrent protection and self-controlled heater devices, where the polymer materials used have a positive Temperature Coefficient. Examples of positive temperature coefficient (PTC) polymeric materials and examples of devices incorporating these materials are disclosed in the following U.S. patents: ...

AI Technical Summary

Problems solved by technology

Fabrication of useful devices with bulk resistivities below approximately 0.2 Ω-cm has not yet been achieved

First, there are inherent difficulties in the fabrication process when dealing with such low bulk resistivities

Second, a device with such a low bulk resistivity would not have a large PTC effect, making it very impractical as a circuit protection device

Thus, there is an inherent limit on the maximum holding current value that can be obtained for any given footprint of the device

Images