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Flux Applicator System for Substrates

IP.com Disclosure Number: IPCOM000034424D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Related People

Sullivan, JL: AUTHOR

Abstract

A technique is described whereby a flux applicator provides even distribution of flux to substrates by accurately dispensing the flux without making contact with the substrate. Two methods of applying the concept are discussed, one by means of an atomizer spray and the other by means of a slide containing a hole pattern. In prior art, contact fluxing of substrates, as used in the fabrication of circuits, caused uneven distribution of flux. This unevenness was caused by the surface tension of the flux adhering to the applicator as the applicator was pulled away from the surface being fluxed. The two methods described herein implement a flux applicator system to dispense the flux evenly and accurately over the entire surface area. Two concepts of non-contact fluxing are described.

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Flux Applicator System for Substrates

A technique is described whereby a flux applicator provides even distribution of flux to substrates by accurately dispensing the flux without making contact with the substrate. Two methods of applying the concept are discussed, one by means of an atomizer spray and the other by means of a slide containing a hole pattern. In prior art, contact fluxing of substrates, as used in the fabrication of circuits, caused uneven distribution of flux. This unevenness was caused by the surface tension of the flux adhering to the applicator as the applicator was pulled away from the surface being fluxed. The two methods described herein implement a flux applicator system to dispense the flux evenly and accurately over the entire surface area. Two concepts of non-contact fluxing are described. Both methods involve the spraying of the flux onto the substrate. The first method, as shown in Fig. 1, involves atomizing the flux into an air stream at a controlled rate in a steady-state condition. When required, the stream of air with the flux mist is diverted to the site on the substrate for the appropriate length of time to give the nominal flux coverage. Cleaned and regulated compressed air passes through an atomizer where

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it picks up a very fine mist of flux particles. The rate of flux atomized into the air stream is controlled by the drip rate in the atomizer. The air stream carrying the flux particles passes through a valve which directs it to a recovery tank where the flux is removed from the air. The valve diverts the air stream with the flux particles to the flux applicator where it is sprayed through a nozzle onto the substrate. Based on the atomization rate and flux coverage requirements, the length of time to keep the air stream diverted is determined. At the appropriate time, the valve will shift the stream back to the recovery tank. The shape of the outlet of the flux applicator determines the shape of the flux site. The flux ...