Collaboration Between OEM and EMS to Combat Head on Pillowing Defects: Part 2 - Warpage Acceptance Proposal
Bibliographic record
Abstract
ABSTRACT This paper is in English and Chinese languages. There have been many publications, industry workshops, and symposia that describe process mitigation techniques for minimizing the occurrence of Head-on-Pillow (HoP) defects during surface mount assembly. These include inspection effectiveness as covered in Part 1 of this two paper set. This second paper addresses the root cause of the HoP defect; specifically the link between HoP defects and component warpage. Multiple case studies contributed by the participating companies are presented to support the proposal that the current industry warpage standard needs to be revised and to demonstrate that further work is needed by the industry to understand the root cause of this defect better. Based on the data from the case studies, the authors propose revised acceptance criteria that set the maximum warpage at O.090mm (3.5mil) for BGA of O.8mmpitch and above.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.033 | 0.028 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.005 |
| Research integrity | 0.006 | 0.002 |
| Insufficient payload (model declined to judge) | 0.011 | 0.003 |
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 source (direct Gemma or distilled Codex), 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".