Technical Articles
In-depth technical content for semiconductor process engineers. Learn about gas flow units, MFC operation, and process control fundamentals.
What is sccm?
Understanding standard cubic centimeters per minute (sccm), the standard unit for volumetric gas flow in semiconductor manufacturing.
Read article →sccm to kg/hr conversion in semiconductor processes
Practical guide to converting between volumetric (sccm) and mass flow (kg/hr) units for process recipes.
Read article →Why MFC accuracy affects yield
How Mass Flow Controller precision impacts semiconductor process control and final device yield.
Read article →Vacuum unit conversion basics
Understanding Torr, mbar, Pa, and other vacuum pressure units used in CVD and etch processes.
Read article →Gas density vs molecular weight
Relationship between molecular weight and gas density at STP, and implications for flow calculations.
Read article →Vacuum conductance and effective pumping speed
How piping conductance and pump speed combine to determine the effective pumping speed seen by the chamber.
Read article →Throughput, leak rate, and the rate-of-rise method
Using throughput units and the pressure rise test to quantify leaks and gas loads.
Read article →Outgassing load estimation and base pressure
Estimating outgassing load from area-based outgassing rates and predicting approximate base pressure.
Read article →Pumpdown log analysis for S/V and gas load
Using measured pumpdown logs to extract S/V, effective pumping speed, and approximate gas load.
Read article →Gas mixture composition and partial pressures
Relating MFC flow settings to mole fractions and partial pressures in a non-reactive gas mixture.
Read article →Impingement rate, monolayer time, and Langmuir exposure
How pressure and gas species determine surface flux, monolayer formation times, and Langmuir exposures.
Read article →Mean free path in vacuum systems and PVD processes
What mean free path (λ) means, how pressure and gas species affect it, and why it matters for sputtering, evaporation, and chamber design.
Read article →Pumping speed and throughput: understanding Q = S × P
How volumetric flow, pressure, and pumping speed relate in vacuum systems—and how to size pumps and throttles for process gas loads.
Read article →Pumpdown time prediction: pump curves, conductance, and gas load
How to estimate chamber pumpdown curves using pump speed vs pressure, piping conductance, and total gas load—before you run the recipe.
Read article →STP, NTP, and standard conditions for gas flow units
Why sccm and slm depend on standard temperature and pressure definitions—and how mismatched references cause conversion errors in recipes.
Read article →Molecular vs viscous flow in vacuum piping
How to identify flow regimes from pressure and geometry, and why conductance formulas change between molecular and viscous conditions.
Read article →MFC calibration basics for process engineers
Zero check, span verification, calibration intervals, and common failure modes that affect gas flow accuracy in CVD and etch tools.
Read article →slm vs sccm: choosing flow units in semiconductor recipes
When to specify standard liters per minute vs standard cubic centimeters per minute, and how to avoid order-of-magnitude errors in gas panels.
Read article →What is MFC gas correction factor?
How K-factors relate calibration gas (usually N₂) to process gases, and how correction affects delivered flow in semiconductor gas panels.
Read article →Why actual pumpdown time differs from theoretical calculation
Practical reasons pumpdown curves deviate from simple exponential models—pump curves, conductance, outgassing, and leaks.
Read article →Outgassing in vacuum chambers: meaning and effect
What outgassing is, which materials dominate, and how Q_out limits base pressure after pumpdown.
Read article →Base pressure vs process pressure in vacuum systems
Distinguishing idle base pressure, crossover pressure, and recipe process pressure—and which tool to use for each.
Read article →How to interpret gas flow conversion results
Sanity checks after converting sccm to kg/hr or g/min—what to compare and common misreads.
Read article →Common mistakes in semiconductor vacuum calculations
Frequent unit, regime, and assumption errors when using vacuum and gas-flow calculators in fab work.
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