ดาวน์โหลด All Proceeding - AS Nida

Table 5. ANOVA with all Main Effects and Interactions.
Sources P-Value for the Etched Rate
A 0.001
B 0.029
C 0.371
A*B 0.791
A*C 0.675
B*C 0.169
A*B*C 0.201
Centre Point 0.162
In order to determine the appropriate setting of the process
variables, the main effects were plotted in Fig. 5. The appropriate levels
of process variables A and B are set at 60 and 3.1, respectively. After an
implementation of the new operating condition, the response of the
etched rate is improved with the deviation of 1.365 and the three sigma
level of 4.1 (Fig. 6)
Mean
Frequency
16.8
15.6
14.4
13.2
12.0
16.8
15.6
14.4
13.2
12.0
40
30
20
10
-1
1
Main Effects Plot for Range
Data Means
A
0
C
2
1
Fig. 5 Main Effect Plots of the Etched Rate Analysis.
0
43.5
Histogram of Etched rate (Main effect)
Normal
45.0
46.5 48.0 49.5
Etched rate
-1
51.0
B
0
52.5
1
Mean 46.84
StDev 1.365
N 216
Fig. 6 Etched Rate Performance Measure at New Process Condition
from the Factorial Design.
55
The method of multiple regression analysis at 95%
confidence interval is then applied for statistically significant process
variables to determine the most preferable fitted equation of associated
process variables of A and B to the response of the etched rate (Table
6). The relationship of the process variables and the response (RER) in
terms of the path of steepest descent is
Expected Response of RER = 63.1-0.171A-13.9B. (3)
Table 6. Regression Model including its Significant Coefficients and
ANOVA Table.
Predictor Coef SE Coef T P-Value
Constant 63.14 17.31 3.65 0.002
A -0.1708 0.0382 -4.47 0.000
B -13.875 5.738 -2.42 0.027
Source DF SS MS F P-Value
Regression 2 135.86 67.932 12.90 0.000
Residual 17 89.557 5.268
Total 19 225.42
The preferable levels of process variables A and B from the
path of steepest descent are 60 and 3.8, respectively (Table 5). When
the new levels of process variables have been applied, the new etched
rate is improved with the deviation of 1.124 and the three sigma level of
3.4 (Fig. 7).
Frequency
30
25
20
15
10
5
0
37
Histogram of Etched rate (Multiple regression)
Normal
38
39
40 41
Etched rate
42
43
Mean 39.50
StDev 1.124
N 216
Fig. 7 Etched Rate Performance Measure at New Process Condition
from the Steepest Descent.