An investigation into the effect of dry bake on the solderability degradation of electrodeposited tin finishes

The solderability of component termination finishes degrades upon storage due to the combined effects of surface contamination, oxidation, corrosion and/or intermetallic compound (IMC) formation at the interface between substrate and finishes. Such solderability degradation impinges on the shelf-life of the electronics components and hence demands an in-depth understanding to ensure high reliability Pb-free soldering. This paper is concerned with the effect of the 155°C dry bake precondition on the accelerated ageing of bright Sn electrodeposited termination finishes over Cu substrates. Two coating thicknesses, 2.5 μm and 9 μm, were studied as-received and dry baked for 4 hr and 16 hr as per industrial standards and analysed with respect to their solderability, microstructural and compositional characteristics. It was found that, with increasing dry bake time, both the thickness variations experienced continued solderability degradation, with only the 2.5 μm thick coatings failed after 16 hr of dry heat. Such a loss of solderability was primarily contributed to the exposing of Sn-Cu IMCs. The thickness safety margin (i.e. maximum IMC thickness) for the dry bake condition (16 hr) of the given bright Sn samples was identified to be around 2.5 μm, which could provide a guidance for any future industrial initiative to further reduce coating thickness. Besides, the dry bake conditions have proven to be a consistent and reliable precondition approach for the Sn-based metal finishe

Additional file 1: of Perceived access and barriers to care among illicit drug users and hazardous drinkers: findings from the Seek, Test, Treat, and Retain data harmonization initiative (STTR)

Supplemetal Tables S6 (Summary of the STTR studies included in this study), S7 (Comparison of proportions reporting no or low social support by gender and HIV status), S8 (Comparison of proportions reporting low perceived access to care and greater barriers to care by gender and HIV status), S9 (Multivariable regression models assessing association of drug use and hazardous drinking with the mediator variable (social support), stratified by HIV status). (DOCX 23 kb

Stellaria longifolia Mühl.

原著和名: ナガバツメクサ科名: ナデシコ科 = Caryophyllaceae採集地: 北海道 川上郡 標茶町 塘路 (北海道 釧路 標茶町 塘路)採集日: 1974/7/23採集者: 萩庭丈壽整理番号: JH008591国立科学博物館整理番号: TNS-VS-958591備考: DB作成協力会による補足あ

The depression treatment cascade for HIV-infected adults.

<p>The depression treatment cascade for HIV-infected adults.</p

Depression-related outcomes and definitions.

<p>Depression-related outcomes and definitions.</p

Conceptual framework for classification of antidepressant treatment decisions.

<p>Conceptual framework for classification of antidepressant treatment decisions.</p

The depression treatment continuum for patients engaged in HIV primary care.

<p>The depression treatment continuum for patients engaged in HIV primary care.</p

Description of sample.

<p>Description of sample.</p

Antidepressant treatment, treatment adjustments, and remission.

<p>Antidepressant treatment, treatment adjustments, and remission.</p

Distribution of depression and antidepressant treatment status across CNICS sites.

<p>Distribution of depression and antidepressant treatment status across CNICS sites.</p