Source Reduction - Raw Materials Usage Reduction
TSMC seeks to optimize processes to minimize raw material use and waste production, protecting the environment while reducing costs at the same time. TSMC has a designated unit that periodically reviews raw materials reduction performance. Internally, we optimize our process recipe for raw material usage, which can not only reduce production cost but also reduce the generation of pollutants and wastes. Externally, we require our process tool suppliers to review and minimize the chemical usage step by step. We are now discussing with our process tool suppliers to adopt the SEMI-S23 guideline to optimize the consumption of energy, resource and chemicals. We have also included SEMI-S23 as a process tool procurement specification.
Water Pollution Control
TSMC’s water pollution control strategy is first to reduce pollutants in process wastewater, followed by water recycling and treatment of pollutants in water. Effluent water quality must be better than or compliant with governmental standards.
|Advanced wastewater recycling system can reduce energy and
resource consumption and waste generation.
TSMC’s major water-using process is an ultra-pure water system which turns raw water into ultra-pure water mainly used in process tools for cleaning chemical residue on wafer surfaces. To reduce total water usage, TSMC’s effluent water from ultra-pure water systems and process tools are graded by purity. The cleanest is reused in the manufacturing process; the second grade taken from the recycling treatment is employed in secondary uses such as cooling-tower water. Wastewater that cannot be recycled is discharged to treatment facilities for final wastewater treatment.
TSMC adopts a strict front-end wastewater categorization strategy to improve treatment efficiency. Wafer fabs’ wastewater can be divided into fluoride, copper, general acid, and various polishing wastewaters. All kinds of wastewater are strictly categorized at process tools, and collected to wastewater treatment facilities through separated piping. In order to manage these drains strictly, there are more than 20 categories of drainage types, carefully operated and maintained by professional teams to comply with the standards of the Science Park Administration (SPA). The water is then discharged to the SPA wastewater treatment plant for further treatment after professional teams ensure the discharge complies with SPA standards. The treated wastewater is discharged to rivers from the SPA’s wastewater treatment plants in compliance with river discharge standards. The SPA also conducts random measurement of the discharges of each company in Science Park.
TSMC operates only after ensuring that the environment will not be polluted. Each fab is equipped with effective wastewater treatment systems including complete backup systems, such as emergency power supplies, to reduce the likelihood of abnormal discharge. Operating status of all of TSMC wastewater treatment systems are monitored 24 hours a day by shift personnel. If operating conditions diverge from the preset limits, a warning signal is sent and wastewater discharge is halted. Data gathered for monitoring system effectiveness have been designated an important tracking item to ensure effluent quality.
Developing New Technologies to Response to New Regulations
In addition to complying with SPA standards, TSMC continually works with industries and universities to improve discharge quality in areas such as COD (Chemical Oxygen Demand), TMAH (Tetra-methyl ammonium hydroxide) and NH3-N to reduce hazards to water bodies. For example, we reduced COD discharge for 12-inch fabs by 62.5%.
In addition, TSMC continues to explore new wastewater treatment and chemical recycling technologies. For example, TSMC led the industry in performing a series of experiments to obtain the optimal processing technology for NH3-N-containing backside grinding wastewater, high-concentration fluoride and phosphorus acid wastewater and TMAH recycled by external contractors, which attests to our dedication to protecting the environment.
Air Pollution Control
TSMC’s air pollution control strategy is to optimize process to reduce pollutants in air exhaust, and then to abate pollutants in air exhaust through high-efficiency equipment to comply with or surpass legal requirements. Air pollutant concentrations in TSMC’s exhaust are far below the standards required by Taiwan’s EPA, according to actual measurements performed over the years.
Wafer fabs emit three major types of exhaust: acid exhaust, base exhaust, and volatile organic compounds. Heat exhaust emitted by process equipment does not cause air pollution. Air pollution control systems depend on various categories and characteristics of pollutants. TSMC installs local scrubbers behind process tools in order to treat toxic, flammable and PFC gases. First, high temperatures or other physical and chemical measures are used to significantly reduce the concentration of pollutants in tool exhaust. The gas is then inducted to central waste gas treatment equipment for end-point treatment. Endpoint treatment includes zeolite-rotary-wheel absorbing equipment for volatile organic compounds (VOC) treatment and wet scrubber equipment for acid or base gases.
Waste Reduction and Resource Recycling
|Our air pollution control systems surpass local standards.
TSMC has made great efforts in reducing raw materials usage with significant achievements on waste reduction and recycling over the past decade. Although the categories of wastes are growing more complex, TSMC continued to develop new waste recycling technology with potential suppliers to raise its recycling rate and reduce waste disposed in landfills. TSMC’s Taiwan sites continued to carry out reduction and recycling programs in 2013, and our waste recycling rate reached 92%, exceeding 90% for the sixth consecutive year, while our landfill rate was below 1% for the sixth consecutive year. Our overseas subsidiaries are also endeavoring to improve their waste recycling rates.
TSMC initiated several environmental programs which focused on selected less-hazardous chemicals for reduction, recycling and reuse. For example:
Computer Reuse and Recycling Campaign
||Process chemical replacement:
Replaced copper etching chemicals with heavy metal-free chemicals to reduce environmental impact, reducing waste by 52%, or 5,300 tons.
||Chemical Waste Recycling Technology Development:
Chemical Waste Recycling Technology Development Worked with supplier to develop a method to re-use developer fluid in other industrial processes to conserve natural resources and reduce ammonia waste; recycled 6,095 tons of developer fluid in 2013.
TSMC fully supported ASUSTek Computer Inc.’s "Computer Reuse and Recycling Campaign"
project. The Ministry of Economic Affairs also supported this campaign. TSMC has donated more than 41,227 used personal computers, notebook computers, and LCD monitors since 2007, making up one-third of the total amount received in this project to become the largest donor.
Our purpose in participating in this campaign is to promote the concept of material recycling. Through this recycling campaign, refurbished computers are donated to students in rural elementary and junior high schools and to disadvantaged minorities to narrow the digital divide, caring for society and protecting the environment at the same time.