Toshihiro Miyake

Hydrocarbon fluxes for ionic compound free soldering

Purpose – The purpose of this paper is to develop a new ionic compound free soldering process.Design/methodology/approach – The ability of hydrocarbons including 9,10‐dihydroanthracene, eicosane, 2,6,10,14‐tetramethylpentadecane, cyclooctane, and dicyclopentadiene to reduce cuprous or cupric oxide was investigated. The applicability of hydrocarbons as ion free flux reagents was experimentally examined. The hydrocarbons were applied to the soldering of pre‐oxidized copper electrodes under practical conditions.Findings – A 9,10‐dihydroanthracene was found to be efficient at reducing cuprous or cupric oxide powder under an argon atmosphere at 300°C for 2 min. The high‐reducing ability of the hydrocarbon is in agreement with the low‐homolytical C−H bond dissociation energy calculated based on the density functional theory. A 9,10‐dihydroanthracene was shown, by the highest soldering efficiency and sufficient reliability in the environmental testing, to be applicable as an ion‐free soldering flux.Originality/v...

Fluxless solder joining using alkane

Abstract Electronics products are becoming smaller these days. Thus the technology to connect fine pitch electrodes is very important. We developed a new soldering method without applying any flux, which deteriorates the insulation property between electrodes. In the ordinary soldering method, flux is used to dissolve the oxide film. In the new method, we have introduced alkane to remove oxide film by physical reaction. When heat is applied and alkane is boiled, volume expansion energy breaks the oxide film and the desirable clean solder surface is obtained. As a result, the connections become as strong as using the ordinary method.

Hydrocarbon fluxes for ionic compound free soldering: improvement by peroxide additives

Purpose – The paper aims to focus on lowering the soldering temperature of ionic compound free soldering using 9,10‐dihydroanthracene as a hydrocarbon flux.Design/methodology/approach – The ability of 9,10‐dihydroanthracene to reduce cupric oxide in the presence of peroxides including tert‐butyl peroxybenzoate, tert‐butyl cumyl peroxide, tert‐butyl peroxide was investigated. The applicability of 9,10‐dihydroanthracene in the presence of peroxides as ionic compound free flux reagents was experimentally examined in the soldering of pre‐oxidized copper electrodes under practical conditions.Findings – The ability of 9,10‐dihydroanthracene for the reduction of cupric oxide powder under argon atmosphere at 300°C for 120 s was found to be improved in the presence of tert‐butyl peroxybenzoate. The highest reducing ability of 9,10‐dihydroanthracene in the presence of tert‐butyl peroxybenzoate among the peroxides was in agreement with the lowest homolytical O–O bond dissociation energies of the peroxides calculated...

Development of the embedded LSI technology in PALAP/spl trade/

We are developing the embedded LSI technology in PALAP/spl trade/; PWB developed by DENSO CORP.; made from plural patterned thermoplastic resin films and fabricated with one time hot press process. To understand the behavior of the resin, via, copper land, LSI and so on during press process, a new strong coupling analysis system was developed. Using this system, we analyzed the velocity of resin around the LSI, when embedding the LSI. As a result, it was cleared that the resin under the LSI flowed toward the clearance, and the velocity sharply increased at peripheral position of the LSI. Practically, via under the LSI radially moved from the LSI central part according to the velocity distribution. It is not concerned with the positional relationship between the LSI bump and via that the clearance is different from each other at the left right of the LSI, because the LSI moves with the resin at the same timing and velocity.