Plasma Treatment for Fluxless Flip-Chip Chip-Joining Process
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Flip-Chip technology is a well-established solution to increase the number of connections between a chip and a PCB. Unfortunately, with large die and high bump density, flux residues cleaning is increasingly challenging. Fluxless soldering is becoming more attractive given that flux residues cleaning step can be avoided leading to a more environment friendly process while reducing water consumption and chemical waste. Hydrogen radicals are known as a reducing agent to remove metal oxide. We present here assembly tests performed in an industrial-like environment where a hydrogen-based plasma treatment is used to suppress bumps oxide in replacement of flux chemical. The plasma treatment is performed in a vacuum capacitively coupled plasma chamber with a gas mixture containing a percentage of hydrogen. We use large 20 × 20 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> chips and associated organic substrate, which bumps (80μm diameter and 185.6μm pitch) and pads are made of a tin-based lead-free solder. The plasma treatment is perform on both the chip and the substrate prior to assembly using furnace mass reflow. We have successfully demonstrated the assembly of several dies using a standard mass reflow furnace. In the idea of process industrialization, re-oxidation kinetic shown a process window of 48 hours between plasma treatment and chip-joining, as shown by chip-pull, optical microscopy inspection and deep thermal cycling reliability test.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it