Laser micromachining for microfluidic, microelectronic and MEMS applications
Bibliographic record
Abstract
"Summary form only given". Laser micromachining of dielectrics and metals is a versatile fabrication and repair tool for applications in micro-fluidics, microelectronics and MEMS. Issues such as ablation threshold, ablation rate, incubation of damage at subthreshold fluences, edge resolution, debris creation and residual substrate damage are all important in determining the suitability of this technique for these applications. An extensive study is being carried out on drilling of holes in glasses of interest to microfluidic systems using both nanosecond UV laser pulses at 266 nm and femtosecond pulses at 800 nm. The drill rate and maximum ablation depth has been measured for various holes sizes ranging from 25 to 100 /spl mu/m in diameter. The resultant morphology is measured using an optical microscope and a scanning electron microscope showing that redeposition and loss of beam fluence down the hole limits the maximum hole depth for a given entrance laser fluence. The results indicate that, in some cases at deep depths near the end point of the hole, the shape may no longer be round. Cracking around the entrance of the hole is also observed with nanosecond drilling and a new technique involving heating of the substrate during the laser interaction is being studied to try to reduce the degree of cracking. Redeposition of glass around the entrance of the drilled hole, which complicates applications where contact must be made to an adjoining surface, is another issue. In order to minimize redeposition, techniques of using a protective sacrificial layer are being investigated. In particular, the use of a protective tungsten thin film which can be stripped off, taking the overcoated debris with the film, is being investigated. In order to understand the microscopic processes occurring within the material and to predict the expected ablation thresholds, ablation rates and residual damage to the material structure, a molecular dynamics simulation code is under development to model the ablation of silicon and the ablation of glasses. Current experimental results and theoretical understanding will be presented in this paper.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.057 | 0.022 |
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".