台積電於官方網站公告，二奈米製程已於2025年第四季正式進入量產。這是台積電首度捨棄沿用 15 年的 FinFET，轉向GAA奈米片（Nanosheet)電晶體，成為產業最尖端的技術里程碑。

相較 3 奈米 N3E，此製程在相同功耗下速度提升 10% 至 15%，或在相同速度下功耗降低達 25% 至 30%。其卓越的能源效率與晶片密度，為 AI 運算、高效能運算及智慧型手機提供了強大的核心驅動力，進一步鞏固台積電的技術領先地位。

然而二奈米技術背後隱藏著龐大的環境成本。由於 GAA 奈米片微縮技術的導入與「晶圓減薄堆疊」製程日益複雜，生產過程中不僅涉及更密集的 EUV（極紫外光）曝光程序，亦大幅增加了晶圓削切、研磨與精密清洗的次數。這使得每單位晶圓的耗電、耗水與廢棄物產出，皆較傳統成熟製程呈現前所未見的爆炸性增長。

以竹科寶山二期四座 2 奈米廠的用水為例，環評估計每日用水量高達 9.8 萬噸，單一廠區便占新竹地區總用水量的 16% 至 18%。對於水情長年吃緊的新竹地區而言，能否負荷如此巨大的新增用水需求，始終是環評過程的爭議核心。為此，台積電曾承諾寶山 2 奈米製程將於 2030 年達成「100% 使用再生水」，以降低對民生自來水系統的衝擊。

遺憾的是，「2030 全面使用再生水」的承諾，已於 2025 年 10 月正式宣告跳票。原先計畫由竹科自建每日 3 萬噸再生水廠，並搭配新竹縣、市每日 6.8 萬噸的市政再生水共同供應。然而，由於新竹縣政府對污水下水道接管及再生水中心建置的配合意願低落，導致市政再生水供應期程延宕；同時，園區自建再生水廠也因工程進度落後，無法如期上線(註1)。

面對承諾跳票，竹科管理局於 2025 年被迫申請辦理環境影響差異分析，全面延後再生水使用期程並取消「百分百使用」之承諾。此舉再度引發外界疑慮：水課題是否將成為 2 奈米產能的「天花板」？又是否會衝擊大新竹地區的民生與農業用水安全？

從區域供需平衡來看，再生水承諾的破局將導致 2 奈米廠對自來水系統的依賴高峰，從原先預計的 7.3 萬噸飆升至 8.7 萬噸。預測在 2028 至 2029 年產能全開時，因再生水廠尚未到位，大新竹地區的供水餘裕率將面臨極限挑戰，最劣情境下僅存 2.5% 至 2.8%（約 2.2 至 2.5 萬噸），是供水韌性的重大挑戰(註2)。

而「廢水排放量」也可能產生對產能的實質限制。根據環評結論，寶山二期許可的每日廢水排放量上限為 3.88 萬噸。原規劃是將每日產生的 6.88 萬噸廢水，由園區再生水廠去化 3 萬噸，剩餘部分才經污水處理後排放至客雅溪。但在再生水廠未能及時運轉的情況下，若台積電每日廢水產生量超過排放量3.88 萬噸上限，即有違反環評結論之虞(註3)。

以此數據回推，在再生水廠運轉前，受限於 3.88 萬噸的排放量限制，2 奈米廠的每日用水量上限僅能維持在 5.57 萬噸。這意味著，寶山二奈米的產能利用率恐被迫壓低至 56% 左右，才得以符合環評法規(註4)。

隨著 2 奈米製程正式量產，這頭資源消耗的「哥吉拉」對環境的衝擊將逐漸浮現。針對水資源與廢水排放問題，除了應加速建置再生水量能，台積電也可重新思考於再生水基礎設施完善之前，主動調節產能利用率，避免犧牲了新竹地區的用水與生態環境。

作者：
許博任（環境權保障基金會副執行長）、彭桂枝（台灣乾淨水行動聯盟理事長）

註1： 新竹科學園區(寶山用地)第2期擴建計畫環境影響說明書第二次環境影響差異分析報告 (定稿本)，4-3頁。
註2：新竹科學園區(寶山用地)第2期擴建計畫環境影響說明書第二次環境影響差異分析報告 (定稿本)，6-4頁，表6-2。
註3：新竹科學園區(寶山用地)第2期擴建計畫環境影響說明書(定稿本)，5-3頁，表5-1。
註4：原環評結論每日最大用水量為9.8萬噸，最大廢水產生量為6.88萬噸。本文依前述(最大廢水產生量/最大用水量)比例，回推當每日最大廢水產生量為3.88萬噸時，每日最大用水量約為5.57萬噸，再以5.57萬噸對比原每日最大用水量9.8萬噸，推估產能利用率約為56%。

TSMC’s 2nm Ambitions at Risk: How a Failed Water Commitment Could Choke Production Capacity

Authors: Hsu, Po-Jen (Deputy Executive Director, Environmental Rights Foundation) Peng, Kuei-Chih (Chairperson, Taiwan Clean Water Alliance)

TSMC has officially announced on its website that its 2nm process entered mass production in the fourth quarter of 2025. This marks a pivotal technological milestone as TSMC transitions from the FinFET architecture, used for the past 15 years, to the cutting-edge GAA (Gate-all-around) Nanosheet transistor structure.

Compared to the 3nm (N3E) process, the 2nm node offers a 10% to 15% speed improvement at the same power consumption, or a 25% to 30% reduction in power at the same speed. Its superior energy efficiency and transistor density provide a robust core engine for AI computing, High-Performance Computing (HPC), and premium smartphones, further consolidating TSMC’s global leadership in semiconductor technology.

However, behind the 2nm breakthrough lies a massive environmental cost. Due to the implementation of GAA Nanosheet scaling and the increasing complexity of “wafer thinning and stacking” processes, production now involves more intensive EUV (Extreme Ultraviolet) lithography exposures and a significant increase in the frequency of wafer dicing, grinding, and precision cleaning. Consequently, the consumption of electricity and water, as well as the generation of waste per unit of wafer, have seen an unprecedented surge compared to mature processes.

Taking the four 2nm fabs in Baoshan Phase II of the Hsinchu Science Park as an example, the Environmental Impact Assessment (EIA) estimates a daily water requirement of 98,000 tons. This single site accounts for approximately 16% to 18% of the total daily water supply in the Hsinchu area. For a region that has long faced water scarcity, whether it can sustain such a massive increase in demand remained a central controversy throughout the EIA process. In response, TSMC pledged that the Baoshan 2nm process would achieve “100% reclaimed water usage” by 2030 to mitigate the impact on the local domestic water supply.

Regrettably, this “100% reclaimed water” commitment was officially declared broken in October 2025. The original plan relied on a combination of a self-built reclaimed water plant within the Science Park (30,000 tons/day) and municipal reclaimed water from Hsinchu County and City (68,000 tons/day). However, due to the Hsinchu County Government’s reluctance to commit to sewage system connections and the construction of reclaimed water centers, the municipal supply timeline has been delayed. Simultaneously, the construction of the Science Park’s own reclaimed water plant has fallen behind schedule[1].

Following this failure to meet commitments, the Hsinchu Science Park Bureau was forced to apply for an Environmental Impact Difference Analysis in 2025, officially postponing the reclaimed water timeline and retracting the “100% usage” pledge. This move has reignited external concerns: Will water issues become the “ceiling” for 2nm production capacity? And will this jeopardize the water security of residents and agriculture in the Greater Hsinchu area?

From a regional supply-demand balance perspective, the collapse of the reclaimed water pledge will cause the 2nm fab’s reliance on the domestic water system to peak at 87,000 tons per day, up from the originally projected 73,000 tons. It is predicted that in 2028-2029, when 2nm capacity is expected to be fully ramped up, the water supply surplus for Greater Hsinchu will face an extreme challenge, dropping to a mere 2.5% to 2.8% (approx. 22,000–25,000 tons/day) in the worst-case scenario—a severe threat to the region’s water resilience[2].

Furthermore, “wastewater discharge limits” may impose a tangible constraint on production. According to the EIA conclusions, the permitted daily wastewater discharge for Baoshan Phase II is capped at 38,800 tons. The original plan was to produce 68,800 tons of wastewater daily, with 30,000 tons being processed into reclaimed water on-site, leaving only the remaining 38,800 tons to be discharged into the Keya River after treatment. Without the reclaimed water plant operational, if TSMC’s daily wastewater generation exceeds the 38,800-ton discharge limit, it risks violating the EIA legal requirements[3].

Based on these figures, before the reclaimed water plant is operational, the daily water intake for the 2nm fabs must be capped at approximately 55,700 tons to stay within discharge limits. This implies that the capacity utilization of Baoshan 2nm may be forced down to approximately 56% to remain compliant with environmental regulations[4].

As the 2nm process enters mass production, the environmental impact of this “Godzilla-scale” resource consumer is becoming increasingly apparent. To address the crisis of water scarcity and wastewater discharge, besides accelerating the construction of reclaimed water infrastructure, TSMC should proactively consider adjusting its 2nm capacity utilization before the necessary infrastructure is in place. This is essential to avoid sacrificing the water security and ecological environment of the Hsinchu region.

References:

• [1] HSPB (2025).Second Environmental Impact Difference Analysis Report for the Hsinchu Science Park (Baoshan Site) Phase II Expansion Project (Final Version), Page 4-3.
• [2] HSPB (2025). Second Environmental Impact Difference Analysis Report for the Hsinchu Science Park (Baoshan Site) Phase II Expansion Project (Final Version), p. 6-4, Table 6-2.
• [3] HSPB (2021). Environmental Impact Assessment Report for the Hsinchu Science Park (Baoshan Site) Phase II Expansion Project (Final Version), p. 5-3, Table 5-1.
• [4] Note on Calculation: According to the original EIA conclusion, the maximum daily water consumption is set at 98,000 tons, with a maximum wastewater generation of 68,800 tons. Based on the ratio (Max Wastewater Generation / Max Water Consumption), when the daily wastewater discharge is capped at 38,800 tons, the corresponding maximum daily water consumption would be approximately 55,700 tons. Comparing this to the original planned demand of 98,000 tons, the estimated capacity utilization rate is approximately 56%.