Fundamentals of mega hertz femtosecond laser ablation and its application in interconnection via drilling
Bibliographic record
Abstract
<p>With the ever increasing demands on electronics and its portability, speed and function, the need for lighter and faster processing chips is always there. 3D stacking of chips is enabled through Inter-chip connections or Interconnect vias, which is used to create the electrical connections that facilitate the stacking. Interconnect vias provide the connectivity between the layers of the physical design, resulting in short connection lengths, which improve performance and decrease power consumption significantly. This thesis proposes a high repetition rate, high power femtosecond laser drilling technique for surpassing the quality and throughput demand posed by the current market. A systematic study of the influence of the laser control parameters such as the repetition rate, pulse energy, intensity, wavelength, pulse duration, ablation threshold, quality and throughput rates is analyzed in detail. Decreasing via diameter and increasing via depth at high repetition rate are noted. A smallest via of 8.39 µm and a deepest via of 121 µm were obtained at 13 MHz and 4.33 MHz respectively. Minimal debris accumulation and exceptional surface qualities were noted at high repetition rates. Theoretical and experimental studies of shockwave effects during laser ablation on via surfaces were analyzed. Systematic process of learning the propagation of shockwaves and generating raised rims in ablated crater is analyzed. Analyzing surface temperature of the target revealed presence of small molten liquid layer at 13 MHz. Newly termed observations, primary and secondary rims, were observed and analyzed under the influence of various laser parameters. Rim line width spacings were seen increasing at higher pulse ;vidth and higher power density. Gas assisted ablation showed decreasing line width spacing due to forced convection. Hence, with the successful results from the studies, the laser system shows the capability of meeting and surpassing the current market demands and considered for commercial applications. </p>
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How this classification was reachedexpand
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 | 0.000 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".