Table 3.
Results of spots characteristics (position, sigma, and skewness) based on daily quality assurance measurements (n = 202)
| Avg. | Range | SPC | |||
|---|---|---|---|---|---|
| 3σ | UCL | LCL | |||
| Spot position‐X (mm) | |||||
| Spot1 (E106) | 0.0 | −0.8–0.8 | ±0.6 | 0.6 | −0.6 |
| Spot2 (E145) | −0.1 | −0.9–0.7 | ±0.6 | 0.5 | −0.7 |
| Spot3 (E172) | −0.1 | −0.9–0.7 | ±0.6 | 0.6 | −0.7 |
| Spot4 (E221) | 0.3 | −0.5–0.9 | ±0.6 | 0.9 | −0.3 |
| Spot position‐Y (mm) | |||||
| Spot1 (E106) | 0.3 | −0.3–0.9 | ±0.4 | 0.7 | −0.1 |
| Spot2 (E145) | 0.2 | −0.3–0.7 | ±0.4 | 0.6 | −0.2 |
| Spot3 (E172) | 0.3 | −0.3–0.8 | ±0.4 | 0.7 | −0.1 |
| Spot4 (E221) | 0.3 | −0.4–0.9 | ±0.4 | 0.7 | 0.0 |
| Spot sigma‐X (%) | |||||
| Spot1 (E106) | −0.3 | −1.8–0.0 | ±0.9 | 0.6 | −1.2 |
| Spot2 (E145) | 0.8 | −4.8–2.4 | ±1.7 | 2.5 | −1.1 |
| Spot3 (E172) | 1.3 | −2.7–2.7 | ±1.9 | 3.2 | −0.4 |
| Spot4 (E221) | −3.8 | −6.5–0.0 | ±2.1 | −1.7 | −5.9 |
| Spot sigma‐Y (%) | |||||
| Spot1 (E106) | 0.0 | −1.8–3.6 | ±1.1 | 1.1 | −1.1 |
| Spot2 (E145) | 0.6 | −4.8–4.8 | ±2.0 | 2.6 | −1.4 |
| Spot3 (E172) | −1.9 | −7.9–5.3 | ±2.7 | 0.9 | −4.5 |
| Spot4 (E221) | −0.7 | −9.4–9.4 | ±3.6 | 2.8 | −4.3 |
| Spot skewness‐X | |||||
| Spot1 (E106) | 0.1 | −0.1–0.2 | ±0.2 | 0.3 | −0.2 |
| Spot2 (E145) | 0.1 | −0.1–0.3 | ±0.3 | 0.3 | −0.2 |
| Spot3 (E172) | 0.0 | −0.3–0.3 | ±0.3 | 0.3 | −0.3 |
| Spot4 (E221) | 0.0 | −0.3–0.3 | ±0.3 | 0.3 | −0.3 |
| Spot skewness‐Y | |||||
| Spot1 (E106) | 0.0 | −0.2–0.2 | ±0.2 | 0.2 | −0.2 |
| Spot2 (E145) | 0.2 | −0.1–0.5 | ±0.2 | 0.4 | −0.1 |
| Spot3 (E172) | −0.2 | −0.4–0.0 | ±0.3 | 0.1 | −0.5 |
| Spot4 (E221) | 0.0 | −0.2–0.3 | ±0.3 | 0.3 | −0.3 |
A relative difference (Δ) was calculated by comparing daily (D) measurements (n = 202) against baseline (B) measurements. Upper control limit (UCL) and lower control limit (LCL) are based on statics process control (SPC) charts. UCL = +3σ and LCL = −3σ are from the average value.