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Similarity Searching for Defective Wafer Bin Maps in
Semiconductor Manufacturing
Chung-Shou Liao, Member, IEEE, Tsung-Jung Hsieh,
Yu-Syuan Huang, and Chen-Fu Chien, Member, IEEE
Abstract—Because high-dimensional wafer bin maps (WBMs) cause var-
ious features, it is difficult to search the similarity among WBMs via con-
ventional pattern recognition methods. This study develops a novel mor-
phology-based support vector machine for defective wafer detection. The
experimental results demonstrate its usefulness in yield improvements on
precision and computation cost.
Note to Practitioners—Semiconductor manufacturing in complicated
nanotechnology is facing tough challenge for quick response to yield
excursion for shortening time to market and reducing the cost to maintain
competitive advantages. Due to the increasing complexity of nanotech-
nology for wafer fabrication, increasingly high inspection costs and yield
loss associated with defective wafers have become a critical concern
of semiconductor manufacturers. Focused on real settings of practical
industrial experiments, this study provides a novel approach to searching
similar WBMs from huge wafer spatial data to quickly identify potential
causes for yield enhancement. This approach was validated in real setting
in Taiwan and the results showed its practical viability.
Index Terms—Data mining, morphology, semiconductor manufacturing,
similarity search, support vector machines, wafer bin maps.
I. INTRODUCTION
With increasingly sophisticated manufacturing processes in the
semiconductor industry, the cost to migrate the required techniques
Manuscript received May 02, 2013; accepted July 15, 2013. Date of pub-
lication August 29, 2013; date of current version June 30, 2014. This paper
was recommended for publication by Associate Editor S. Zhou and Editor H.
Ding upon evaluation of the reviewers’ comments. This work was supported
by the Advanced Manufacturing and Service Management Research Center,
National Tsing Hua University under Toward World-Class Universities Projects
101N2073E1, 101N2074E1 and the National Science Council of Taiwan under
Grant NSC100-2221-E-007-108-MY3, Grant NSC100-2628-E-007-017-MY3,
and Grant NSC102-2221-E-007-075-MY3. (Corresponding author: C.-S.
Liao.)
The authors are with the Department of Industrial Engineering and
Engineering Management, National Tsing Hua University, Hsinchu 300,
Taiwan (e-mail: csliao@ie.nthu.edu.tw; tsungjung.hsieh@gmail.com;
s9934519@m99.nthu.edu.tw; cfchien@mx.nthu.edu.tw).
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TASE.2013.2277603
Fig. 1. An example of defective wafer bin maps: functional bins; defective
bins.
adds substantially to semiconductor production costs. Indeed, for the
semiconductor industry as wafer production and size continues to
grow, the volume of in-line and off-line data required to diagnose
yield conditions is growing exponentially. Furthermore, high-volume
wafer fabrication facilities typically produce thousands of wafers
per week, and many of these wafers are inspected and found to be
defective [1], [2], [3]. In this scenario, yield improvement is critically
important, as is maintaining competitive processes and low die costs
for semiconductor wafers in a fabrication facility.
During the final process of wafer fabrication, Circuit Probe (CP) test
will determine whether the corresponding die is good for packaging
into chip. Spatial patterns of testing results are WBMs that provide
crucial information to identify process failures, as illustrated in Fig. 1.
These patterns are formed by marking the defective wafers, so that
manufacturing engineers may use the patterns of WBMs as clues to
investigate the causes of failures resulting in yield losses. As there are
many WBMs to be evaluated, the judgments in semiconductor manu-
facturing thus far still rely on human labor. As a result, the judgments
may be inconsistent owing to human factors (e.g., fatigue) because of
the substantial workload.
In particular, not only should the defective dies be detected before
package, but assignable causes should also be attributed to reduce yield
and profit loss due to scrapped wafers. During the CP test, wafers are
inspected by retrieving information about defect patterns [4]. More pre-
cisely, WBM patterns can provide information to help better monitor
the processes and products. The WBMs, in many cases, contain charac-
teristic patterns, or signatures, which provide insight into the fitness of
the manufacturing processes. A bin can be conceptualized as a bucket
and viewed by mapping the results of these electrical tests onto a 2-D
space.
These defective patterns are usually associated with specific man-
ufacturing problems, and can provide process and product engineers
with important clues regarding the identification of causes and their so-
lutions in order to improve yields [5]. Stapper [6] indicated that defects
are typically clustered, rather than dispersed randomly over a wafer,
and that these clusters become more evident as the wafer size increases.
In the literature, the three proposed approaches to solving the pattern
recognition problem are stated as: the statistical approach, the heuristic
approach, and the simulation approach [7]. The statistical approach
classifies patterns based on an extracted feature set, and an underlying
statistical model for generating these patterns. The heuristic approach
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