Silicon Peninsula #009 — JSR put the world's first EUV metal-oxide resist line in Korea

Thursday, October 1, 2026 · 5-minute read · Free edition

The tape

Seoul gave back part of its post-holiday jump. The KOSPI closed at 6,838.04, down 0.48%; Samsung Electronics fell 1.47% to ₩268,500 and SK hynix fell 1.39% to ₩853,000. The won ended at ₩1,352.80 per dollar. (BusinessKorea)

New York was mixed rather than risk-off. SOXX rose 0.13% to $568.64 while SPY slipped 0.20% to $762.63. Nvidia gained 0.54% to $228.38, AMD rose 0.72% to $611.76, and Broadcom fell 1.10% to $351.19. Micron's fiscal-fourth-quarter call began after the close; the result was not on the company's public quarterly-results page at our 06:31 KST cutoff, so we do not manufacture a print. (SOXX, SPY, NVDA, AMD, AVGO, Micron IR)

Three signals

1. JSR opened the world's first dedicated EUV metal-oxide resist production base in Ochang. The Korean subsidiary completed the plant on September 30, putting the final manufacturing step for metal-oxide resist, or MOR, next to Samsung and SK hynix. JSR bought Inpria in 2021 and disclosed the Korean plan in 2024, with operation targeted for 2026; yesterday turned that roadmap into a working supply node. MOR absorbs EUV more strongly and resists etching better than conventional chemically amplified resists, helping keep ever-smaller patterns upright. Why it matters: Korea has long imported strategic photoresist chemistry from Japan. This plant does not localize ownership, but it localizes finishing, quality assurance and response time. In lithography, where a material change can require long customer qualification, proximity is a commercial moat as much as a logistics one. The key follow-up is qualification: a ribbon cutting matters only when wafers using Ochang material enter sustained high-volume production. (THE ELEC, JSR 2024 decision, Electronic Times)

2. Kolon is expanding the low-loss plastic underneath faster AI boards. Kolon Life Science will raise annual polyphenylene oxide capacity at Gimcheon to 5,400 tonnes, adding a reactor and upgrading equipment for operation in the first half of 2027. PPO is the feedstock for modified PPO used in copper-clad laminates; its insulation performance is reported at three to five times that of epoxy, reducing signal loss in AI and 6G hardware. Kolon transferred mPPO technology and rights to Kolon Industries for ₩17B last year, while continuing to supply the upstream material. Why it matters: the group is aligning raw-material capacity with its downstream laminate chemistry instead of waiting for imported feedstock. That is a modest but measurable vertical-integration bet on higher-frequency boards. The evidence to watch is utilisation after start-up, not announced tonnes. (THE ELEC, Seoul Economic Daily English)

3. Hyundai Mobis is turning localisation from a slogan into a test queue. Eighteen companies and institutions joined an Industry Ministry-backed future-car agreement. Mobis will give fabless vendors the device list and specifications it needs, while research bodies build vehicle-level validation; the stated starting point is only about 5% domestic content in automotive semiconductors. The same group will build a standard software-defined-vehicle platform for mid-sized automakers. Why it matters: Korea's fabless bottleneck is often demand qualification, not first silicon. A Tier-1 buyer defining requirements and providing an in-vehicle route can shorten the gap between a prototype and revenue. The caveat is that an MOU has no volume commitment. Count qualified parts and purchase orders, not participating logos. (ChosunBiz, Hyundai Mobis)

Korea-only radar

FST disposed of 149,614 treasury shares for ₩4.656B, and no English report was found as of 06:48 KST. The September 30 DART filing shows 140,000 shares at ₩31,200 going to the employee stock ownership association and 9,614 shares at ₩29,940 going to employees. FST retained 63,806 treasury shares, or 0.29% of shares outstanding. This is compensation and employee alignment rather than fab investment, but it changes the near-term share count for a Korean EUV pellicle and equipment name that foreign readers track through the technology story. (DART filing 20260930000736)

Number of the day

One — the Ochang facility is JSR's first MOR production base worldwide. The most advanced resist supply chain is becoming geographically closer to the two Korean memory makers that must qualify it. (JSR)

Calendar

• Thu Oct 1, 09:00 KST — Korea's full September trade release; test whether semiconductor exports sustain the strength seen in the first 20 days.
• Thu Oct 1 (US) — Micron post-earnings analyst discussion; listen for HBM4 qualification timing and 2027 supply discipline.
• Thu Oct 1 — Hanmi Semiconductor's US subsidiary was scheduled to be established in October; watch for the corporate filing.
• Fri Oct 2 — Korea market digestion of trade data and Micron's full commentary.
• Thu Oct 8 — TSMC September revenue, the next foundry demand cross-check just beyond this seven-day window.

Silicon Peninsula publishes Korean semiconductor signals on Monday, Wednesday and Friday, with additional alerts when material primary documents warrant them. This edition was prepared on October 1; the data cutoff and calendar above refer to that date. Numbers are quoted from the linked sources. Reply with a company or a decision you need to track. We are preparing a 30-day Korea Watchlist Pilot for the first five clients ($99); reply to request the scope before payment.