A study on high-density high-speed SerDes design in buildup flip chip ball grid array packages
Bibliographic record
Abstract
A study on high-density high-speed SerDes (HHS) designs in buildup laminate flip chip ball grid array (fcBGA) packages is presented in this paper. Experiences have shown that three main capacitive discontinuities happen in flip chip bump area, core PTH via area and BGA transition area. Literature [1] have studied three PTH via configurations for differential pairs and suggested that a routing structure with PTH via on the top of BGA be the best design option, which implies that all Serdes routings have to be done in buildup layers above the core layer. However, with growing Serdes number, limited buildup layer number and specified X-talk number, one cannot route all Serdes differential pairs in the buildup layers above the core layer. In a result, routing some Serdes differential pairs in buildup layers below the core becomes a must. In our paper, the three PTH via structures in [1] are analyzed in detail. In order to obtain a more realistic electrical performance, we include die bump, package wiring and BGA transition with a small portion of PCB transmission line in our models. Ansoft full-wave HFSS tool is used to run for S-parameters. Measurement data from a test system were used to guarantee the correctness of our model setup including boundary condition, port and material definitions and so on. Our studies have shown that all three PTH via configurations can be optimized and provide a similar level electrical performances up to 15GHz, which means a smaller buildup layer number and a package cost reduction for a given application. Numerical results for a 4-4-4 buildup package optimization are presented to show the merit of our methodology
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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".