The Design And Implementation Of A Miniaturized Chip Thin-film Ignition Resistor

The chip thin-film ignition resistor is a new type of electronic component,which has the characteristics of small size,light weight,easy installation and high energy.The product utilizes the current through two ends to heat the dose to the ignition temperature by generating Joule heat on the resistance.This process can be activated by a rather small external impulse energy with a quick reaction.The product is mainly applied into automobile airbags and safety devices,and can also be widely applied to satellites,civil anti-collision airbags and blasting projects.This resistor,with the consistency and high repeat ability,is the most sensitive explosive component in ammunition,which is usually installed on ignition devices such as the electric fuse.As far as we know,there is no other domestic company that is capable of producing such products.The company which the author works for owns a platform of mature thick film technology,a chip thin-film ignition resistor with self-owned intellectual property rights.To shorten the gap between China and developed countries in the field of resistor is of significance to promote the localization of key auto components and parts and the development of the blasting industry.This paper starts from the practical engineering practice,combining the theories of ignition resistance and the international research experience,to make a report of the development of the chip thin-film ignition resistor which is developed by the author.With a resistance value of 2Ω and a precision value of ±10%,the chip thin-film ignition resistor is2.0mmx1.2mmx0.4mm in the size.Besides,its maximum safety current is0.3A and the safety time is 10 s,with the minimum ignition current of 1.5Aand an ignition time of less than 500 microseconds.The paper mainly consists of three parts:1.The theoretical and technological design of the ignition resistor.The ignition resistor adopts the nickel-chromium alloy foil as the material of the resistor,the FR-4fiberglass board as the substrate material.The resistance bridge is with a length of 600 microns,a width of 100 um,and a thickness of 3.5um.By ANSYS thermal simulation,it has been proved that the theoretical design can realize the ignition.With the combination of the platform of thick/thin-film technology in the company,the author has determined the preparation process of the ignition resistor.2.The research on the preparation process of the ignition resistor.Through the comparative experiments and the orthogonal experiments,the parameter of foiling,photo-lithography,end-capping,cutting,electroplating and other processes of the ignition resistor has been studied and optimized and at last selected the best.In view of the problem that how to electroplate on nickel-chromium alloy foil,the author creatively proposed to add an impact nickel layer as a transition layer to improve the bonding force of the film.3.The test of ignition resistor.By measuring the size and testing resistance,solder ability,soldering heat resistance,ignition of the products in three batches,the test results have proved that the quality of the product satisfies the requirements of technical index.