Semi E143

SEMI E143 defines a test method for measuring how an RF generator's output power and harmonic spectral content vary when the load it drives departs from a perfect match — testing across a defined range of mismatched load conditions rather than at the single, well-matched load E136's output-power accuracy test assumes. E136 verifies that a generator's reported power is accurate at one reference load; E115 characterizes how efficiently a matching network corrects for the plasma's constantly shifting impedance. Neither addresses what E143 actually measures: how much the generator's output power drifts, and how its harmonic content changes, across a specified sweep of load mismatches the matching network hasn't yet corrected — the exact condition a generator experiences every time a plasma strikes, extinguishes, or shifts mid-process before the match network catches up.

Matching network hasn't yet corrected a shifting plasma load
E136 tests accuracy at one matched load; E115 tests the matching network itself
SEMI E143 — RF power variation and spectrum testing under specified loadsMeasures output stability and harmonic content across a mismatch sweep
Standardized test loads spanning a defined mismatch range
Same mismatch conditions tested across every generator vendor
Quantified power variation AND harmonic spectral shift, not just power alone
A mismatched load can generate harmonics a matched-load test never reveals
Fab knows how a generator behaves during the mismatch window every process actually has
Catches a failure mode a single well-matched test load can't expose

The reason this needed a dedicated test method distinct from both E136 and E115 is that a generator's behavior under a perfect load tells you almost nothing about its behavior under the imperfect ones it actually sees in production — plasma strike, extinguish-and-restrike events, and recipe step changes all produce a transient mismatch window before any matching network, however good, fully compensates, and a generator can hold textbook accuracy at a 50-ohm reference load while still producing unacceptable power swings or spurious harmonics the moment the load departs from that ideal, which a matched-load-only test program would simply never catch. E143 closes that gap by making load mismatch itself the independent variable under test, sweeping across a standardized range of mismatched conditions and measuring both power stability and harmonic spectral content at each point, rather than assuming — as every accuracy and efficiency spec implicitly does — that the load is already correct.

Testing the Load Condition Every Other RF Spec Assumes Away accuracy at a matched load says nothing about behavior before the match completes E143's standardized mismatch sweep matched (50Ω) each point: one tested mismatch condition Spectrum measured at a mismatch point f0 2f0 3f0 4f0 spurious 3rd harmonic — invisible at matched load E136 and E115 both assume the load is already correct E143 makes mismatch itself the test variable — exactly the window a plasma strike, restrike, or step change always creates

E143 is what tests the one condition nearly every other RF generator specification assumes has already been resolved — by sweeping load mismatch itself as the independent variable and measuring both power variation and harmonic spectral content at each point, it catches instability and spurious harmonics during the real-world window a plasma strike, restrike, or recipe step change always creates, a failure mode no amount of matched-load accuracy (E136) or matching-network efficiency (E115) testing was ever positioned to find.

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