Page 60 - Vol.43

Tech
Notes
技術專文

environmental protection regulations, and possible protests by TSMC's waste management strategies are primarily
residents in the surrounding areas ; and (2) the rapid increase focused on zero waste. TSMC continuously minimizes resource
in waste quantity may become an unfavorable factor during consumption at the source, adjusts raw material usage
the Environmental Impact Analysis process in the future parameters and technical solutions for process improvements,
when TSMC requests for additional land to support wafer and collaborates with suppliers to achieve material optimization
capacity expansion. Moreover, in furtherance of TSMC social and minimization. After raw materials are used in production
responsibility efforts, we should adopt proactive measures processes, on-site recycling is prioritized so that resources are
to reduce the quantity of waste outsourced for treatment to sufficiently reused to delay the disposal of materials as waste.
demonstrate TSMC's efforts towards environmental protection. TSMC continuously promotes raw material usage reduction.
To effectively reduce the growth of waste quantity We have introduced circular economy management methods
outsourced for treatment, TSMC plans to collaborate with to independently develop waste recycling technology. TSMC
our chemical suppliers to transform the waste into "Electronic also adopts proactive actions to strengthen vendor auditing
Grade" materials for TSMC's use in its wafer manufacturing effectiveness to ensure legal and proper recycling and
activities. In order to accelerate the progress and demonstrate treatment of wastes.
our determination, TSMC plans to build the first Zero Waste Below are literature reviews relevant to the technologies
Manufacturing Center located at Central Taiwan Science the three spent chemicals are going to be converted into
Park with the capacity to recycle 140,000 metric tons of waste electronic grade chemicals.
annually by 2023.
2.1 Waste H 2 SO 4 Regeneration Technology
Tai-Chung Zero Waste Manufacturing(TCZWM) Center
will have six ZWM plants, and one central utility plant(CUP). Taking semiconductor grade sulfuric acid as an example,
The six ZWM plants are Sulfuric Acid Regeneration Plant(SARP), the spent H 2 SO 4 is generally recycled into industrial grade
IPA Regeneration Plant(IRP), Ammonia Regeneration Plant sulfuric acid or synthesized into ammonium sulfate, but
(ARP), Silica Recycling Plant(SRP), Fluoride Recycling Plant(FRP), these can only be called "degraded recycling." This move has
and Solvent Thermal Recovery Plant(STRP). The more details caused the market price of industrial sulfuric acid to drop,
of TCZWM planning, design, and strategies will be discussed in and the ammonium sulphate produced may have contained
the later sections. high amount of the heavy metals. In terms of the concept
of circular economy 3.0, it is better that semiconductor
2. Literature Reviews manufacturers do not just throw away waste sulfuric acid, but
also participate in the recycling process as much as possible.
With the cost of waste disposal rising every year along
By using their own waste sulfuric acid, the process is made
with the green aspirations of customers, businesses large and
by regeneration to practice circular economy. Converting the
small alike are looking to reduce the amount of waste they
past of resources(take), make(make) to discard(waste), a single
generate. In fact, achieving Zero Waste has become a popular
linear life cycle into the multiple life cycles of materials, and
business objective for businesses of all size s and types. [01]
evolving into a true circular economy to achieve process waste
According to Zero Waste International Alliance, "Zero Waste
reduction and environmental sustainability. [02] DuPont's spent
is a goal that is ethical, economical, efficient and visionary,
acid recovery(SAR) process is typically used in the refinery plant
to guide people in changing their lifestyles and practices
to recover sulfuric acid from spent acid waste produced in the
to emulate sustainable natural cycles, where all discarded
alkylation process unit. The impurities were not mentioned
materials are designed to become resources for others to use."
though the MECS dry gas SAR process produces up to 99.2
Zero Waste means designing and managing products and
wt% H 2 SO 4 , which is considered as industrial grade. [03][04]
processes to systematically avoid and eliminate the volume
However, DuPont MECS only produced commercially technical
and toxicity of waste and materials, conserve and recover all
grade H 2 SO 4 with metal impurities to ppb level. The TSMC
resources, and not burn or bury them. Implementing Zero
specification requires ppt level qualities, about 1000 times less.
Waste will eliminate all discharges to land, water or air that are
The other manufacturer, Veolia also produced regenerated
a threat to planetary, human, animal, or plant health.
H 2 SO 4 but the process is about the same as that of DuPont

58