Comparison of Applied Materials DPS chambers used for Poly Si etch processes by plasma parameters

Transcription

1 Page 1 Comparison of Applied Materials DPS chambers used for Poly Si etch processes by plasma parameters Das diesem Bericht zugrundeliegende Vorhaben wurde mit Mitteln des Sächsischen Staatsministeriums für Wirtschaft und Arbeit (Förderkennzeichen 576) gefördert. Die Verantwortung für den Inhalt dieser Veröffentlichung liegt beim Autor"

2 Outline! Motivation - Target of the measurements! Chamber comparison by plasma parameter measurement " Measurements at Poly - Si etch step 1 " Measurements at Poly - Si etch step 2 " Measurements at Poly - Si etch step 3! Summary and conclusions Page 2

3 Motivation - Target of the measurements! At start up of new tools all chambers have to fit the same specifications.! Plasma parameters are helpful to characterize new chambers, because: " They are sensitive to hardware and impacts " We get the measurement results in real time " We can measure on test s and on product s.! Target of these measurements: " No process problem, baseline measurement at two DPS chambers " Base line results can be used later in case of possible tool- or process problems to identify the reason easier! Chamber comparison by measurement on product s: " Poly - Si etch process " 1 split lots, all lots were splited, 5 % of each lot on both chamber Page 3 Motivation

4 Poly-Si etch step 1: Chamber comparison by use of electron collision rate electron collision rate [1 8 s -1 ] electron collision rate of step 1 [mean] vs ! Chamber 1 (blue points) shows one point one " significant higher mean values of electron collision rate relative standard deviation [%] electron collision rate of step 1 [relative standard deviaton] vs one point one! Chamber 1 (blue points) shows " lower relative standard deviation " lower range of relative standard deviation to Page 4 Poly - Si etch step 1

5 Poly-Si etch step 1: Chamber comparison by use of electron density 6 electron density of step 1 [mean] vs. electron density [1 9 cm -3 ] one point one! Chamber 1 (blue points) shows: " slightly lower mean value of electron density " significant larger mean value variation to relative standard deviation [%] electron density of step 1 [relative standard deviation] vs one point one! Relative standard deviation of is slightly lower than at Page 5 Poly - Si etch step 1

6 Poly-Si etch step 1: Chamber comparison by plasma parameters, summary electron collision rate [mean of all ] step 1 1,1e9 electron collision rate [s-1] 9e8 7e8 5e8 3e8 1e8-1e8 electron density [cm-3] electron density [mean of all s] step 1 4,8e9 4,6e9 4,4e9 4,2e9 4e9 3,8e9 3,6e9 3,4e9! Summary of chamber comparison at Poly - Si etch step 1: " Both plasma parameters indicate lower to range at " Mean values of electron collision rate and electron density show opposite behaviour Page 6 Poly - Si etch step 1

7 Poly-Si etch step 2: Chamber comparison by use of electron collision rate electron collision rate [1 8 s -1 ] electron collision rate of step 2 [mean] vs. relative standard deviation [%] one point one electron collision rate of step 2 [relative standard deviation] vs one point one! Chamber 1 (blue points) shows " significant higher mean values of electron collision rate! Relative standard deviation of electron collision rate has the same level and to range in both chambers Page 7 Poly - Si etch step 2

8 Poly-Si etch step 2: Chamber comparison by use of electron density 7 electron density of step 2 [mean] vs. electron density [1 9 cm -3 ] relative standard deviation [%] one point one electron density of step 2 [relative standard deviation] vs one point one Page 8! Chamber 1 (blue points) shows: " significant lower mean electron density " larger mean range to! Chamber 1 shows: " higher relative standard deviation than Poly - Si etch step 2

9 Poly-Si etch step 2: Chamber comparison by plasma parameters, summary electron collision rate [s-1] electron collision rate [mean of all s] step 2 1,6e9 1,4e9 1,2e9 1e9 8e8 6e8 4e8 2e8! Summary of chamber comparison at Poly - Si etch step 2: " Both plasma parameters indicate lower to range at " Mean values of electron collision rate and electron density show opposite behaviour! Results are similar to Poly - Si etch step 1 mainly eledtron density [cm-3] 6,6e9 electron density [mean of all s] step 2 6e9 5,4e9 4,8e9 4,2e9 3,6e9 Page 9 Poly - Si etch step 2

10 Poly-Si etch step 3: Chamber comparison by use of electron collision rate electron collision rate [1 8 s -1 ] 1 1 1,1,1 electron collision rate of step 3 [mean] vs one point one! Chamber 1 (blue points) shows much lower electron collision rate! relative standard deviation [%] Diagram of mean values has a logaritmic scale electron collision rate of step 3 [relative standard deviation] vs one point one! Chamber 1 has slightly lower rel. standard deviation at electron collision rate Page 1 Poly - Si etch step 3

11 Poly-Si etch step 3: Chamber comparison by use of electron density 1 electron density of step 3 [mean] vs. Diagram of mean values has a logaritmic scale electron density [1 9 cm -3 ] 1 5 electron density of step 3 [relative standard deviation] vs., one point one! Chamber 1 (blue points) shows much lower electron density! relative standard deviation [%] one point one Page 11! Chamber 1 shows significantly lower relative standard deviation, but a larger range to Poly - Si etch step 3

12 Poly-Si etch step 3: Chamber comparison by plasma parameters, summary Page 12 Electron collision rate [normalized] u_collra chamber Median Mean Count Electron collision rate vs. chamber Chamber 1 Chamber 2 Chamber e ! Summary of chamber comparison at Poly - Si etch step 3: " range of both plasma parameters slightly lower at " but statistically not significant Chamber e Electron density u_edensity [normalized] chamber Median Mean Count Large difference of absolute values at and 2 # both parameters are normalized for chamber comparison: u i = (x i - x q ) / s Chamber e Electron density vs. chamber Chamber 1 Chamber 2 Chamber e Poly - Si etch step 3

13 Summary and conclusions! Mean electron density: Page 13 " is higher in at all etch steps. " indicates higher plasma density in! Process stability: " Depending on etch step, the relative standard deviation of electron collision rate and electron density show different results.! Range to : " electron collision rate and electron density show significant lower range in at etch step 1 and 2 " no statistical significant difference at etch step 3! As a result we conclude, that plasma parameter measurements indicate higher plasma density and lower to range in.! Plasma parameter measurement is a useful method for tool and chamber comparison. Summary and conclusion