Effect of Ni3Sn4 on the Thermo-Mechanical Fatigue Life of Solder Joints in 3D IC

In this article, the 3D integration with Ni/Sn/Ni joints was conducted using transient liquid phase (TLP) bonding (250°C, 0.2 N) with different bonding time. After TLP bonding, plane-type Ni3Sn4 intermetallic compound (IMC) was observed, and when the bonding time is 180 min, complete Ni3Sn4 was found. The diffusion coefficient D was determined to be 32.4 μm2/min. Based on the finite element (FE) simulation, the results demonstrated that the shear stress and equivalent creep strain increased obviously with an increase in the IMC thickness; the results calculated show that the IMC thickness impacts the fatigue life of solder joints significantly, and the fatigue life decreases notably with an increase in the Ni3Sn4 thickness.

Take-Em!

At what point is a discussion a debate, and at what point is it undue pressure? Is all unwanted pressure a kind of manipulation and violence? In this work of philosophical short story fiction, the narrator is invited by his father to go duck hunting as part of their bonding time. The narrator wants to spend time with his father, but expresses ethical concerns about hunting ducks. The father asserts hunting is a natural part of human evolution. The debate continues as the narrator decides to go on the hunt, but is undecided if he will pull the trigger. The story ends with father and son in the blind just at the moment before the narrator must decide if he is going to pull the trigger.

Computer-aided indirect bonding versus traditional direct bonding of orthodontic brackets: bonding time, immediate bonding failures, and cost-minimization. A randomized controlled trial

Summary Introduction The primary aim of this randomized controlled trial was to compare the time for bracket bonding using either direct or computer-aided indirect bonding; a secondary aim was to assess immediate bracket debondings and cost minimization. Methods Consecutive patients were randomly allocated to two groups (blocks of four, online-generated sequence) using a split-mouth design with a direct and a computer-aided indirect bonding method: group 1 (upper right and lower left quadrants: indirect bonding; upper left and lower right quadrants: direct bonding) or group 2 (opposite situation). The primary outcome was difference in time spent for bonding brackets. The secondary outcome was immediate bracket debondings (at the bonding appointment). Time for indirect bonding was recorded in two steps: digital bracket placement and clinical bonding procedure. Outcome assessment was blinded. Friedman’s ANOVA test was used to assess differences in bonding time. Chi-square test was used to compare immediate debondings. A cost-minimization analysis was undertaken. Results Thirty-seven patients were randomized to group 1 or 2. Ten patients were excluded: 15 patients were analyzed in group 1 and 12 in group 2. Clinical chair time for bonding half a mouth was significantly shorter for computer-aided indirect bonding (12 minutes 52 seconds) than for direct bonding (16 minutes 47 seconds) (P < 0.001). When adding the time for digital bracket placement, the total bonding time (28 minutes 14 seconds) was longer for indirect bonding than for direct bonding (P < 0.001). There was no single immediate debonding with the direct bonding method, while 14 brackets were lost with the indirect bonding method (5.1 per cent) (P = 0.0001). Cost-minimization analysis showed that computer-aided indirect bonding was more expensive than direct bonding. Conclusions The clinical chair time was significantly shorter for computer-aided indirect bonding than for direct bonding. However, the total bonding time for computer-aided indirect, including digital bracket placement, was longer than for direct bonding. There were significantly more immediate debondings with computer-aided indirect bonding than with direct bonding. Under these conditions, computer-aided indirect bonding was more expensive than direct bonding. Registration This trial was retrospectively registered on ClinicalTrials.gov (University of Aarhus Protocol Record 10101). Protocol The protocol was not published before trial commencement.