The Netherlands, Eindhoven. Here the sky was perpetually shrouded by low-hanging clouds, a moist wind carrying the saline scent of the North Sea perpetually sweeping through this city renowned for high technology and design. Unlike Princeton's academic, time-steeped tranquility, Eindhoven's air pulsed with a cool, efficient rhythm—a tangible manifestation of modern industrial tempo.
ASML headquarters—clusters of strikingly modern glass-curtain-walled buildings reflecting frigid light under the somewhat grayish sky. Here, time seemed precisely segmented into nanoscale fragments, each fragment saturated with the urgency of R&D, testing, and optimization. This was the birthplace of the most brilliant jewel on the global semiconductor industry's crown, the sanctuary of lithography technology, and the apex dream for countless chip engineers.
Xiuxiu stood before the floor-to-ceiling window of her office, gazing down at the campus operating with the precision of fine instrumentation below. Neatly trimmed lawns, technicians clad in anti-static suits weaving among them, and in the distance, production workshops marked with stringent cleanliness classifications. Everything was meticulously ordered, representing the extreme of what humanity could achieve in manipulating matter and energy at microscopic scales.
Her office wasconcise and efficient, much like her personal style. Beyond essentialoffice equipment and stacks oftechnical documents, the most conspicuous item was an abstract painting hanging on the wall—a complex network composed of extremely fine lines and light points, as if simulating light's paths in the microcosm. On a whiteboard to the side, densely packed formulas, parameters, and structural sketches covered the surface, with several key sections repeatedly circled and annotated with deeper remarks.
Her fingers unconsciously traced the cool glass, yet her gaze lacked focus. In her mind, yesterday's unpleasant conversation with Department Vice President Mr. Van der Veer replayed with crystalline clarity. It had taken place in an office equally overlooking the campus, yet more lavish and spacious.
"Xiu, you are one of the most brilliant talents on our team!" Mr. Van der Veer, a quintessential, shrewd, and pragmatic Dutch manager, spread his hands, his tone carrying indisputable admiration yet harboring something deeper. "Your understanding of EUV light source systems, especially the Laser-Produced Plasma (LPP) generation mechanism, is phenomenal. The company has exceedingly high expectations for your future. The next generation High NA EUVR&D requires your intellect."
He paused, leaning slightly forward, his blue eyes gleaming with professional fervor. "Stay, Xiu. Here we have the best equipment, the mosttop-tier peers, the mostabundant R&D funding. You can realize everything an engineer could dream of here. Your family has settled here too, haven't they? The Netherlands is a good place."
Xiuxiu remained silent, not responding immediately. She understood clearly the subtext behind Mr. Van der Veer's words—amid shifting international dynamics,Chinese-origin engineers like her, mastering core technologies, were growing increasingly "sensitive" and increasingly "scrutinized." This scrutiny carried a flavor of examination andguardedness.
"Vice President," she finally spoke, her voice calm yet bearing an unalterable firmness, "thank you for the company's and your generous regard. But, I have already made my decision."
Mr. Van der Veer's smile froze slightly. He leaned back in his chair, crossing his hands on the desk. "Is it because of... the recent 'trade restrictions'? Xiu, you must understand, that's a matter at the political level,games between nations. Science knows no borders; technology should serve all humanity. ASML has always upheld this principle."
**"Science knows no borders, but technology has borders, and engineers have homelands."**
These words Xiuxiu did not voice aloud, yet they resonated clearly within. She remembered her father—that veteran engineer who had toiled a lifetime in domestic laser technology—who, upon learning of her decision to return, fell into prolonged silence during their transoceanic call, eventually uttering with a tremor and immense gravity: "Xiuxiu, home... needs you."
She recalled years earlier, how that sudden, unexpected ban had, like an invisible iron curtain, instantaneously obstructed the advancement paths of numerous domestic tech enterprises, how it nearly rendered futile thepainstaking efforts of countless peers. That suffocating sensation of being strangled, even overseas, she felt viscerally.
Thelithography machine—this pinnacle creation of human industrial civilization, this colossal apparatus costing upwards of a hundred million euros, composed of over a hundred thousand precision components—its core could be clearly dissected into three major systems, like the three principal pillars supporting a crown.
**Light Source System**—the lithography machine's "heart." It generates light of specific wavelengths, like the most delicate engraving tool. From earlymercury lamps (g-line, i-line), todeep ultraviolet, DUV lithography machines using argon-fluoride (ArF) excimer lasers (193nm wavelength), to the mostcutting-edgeextreme ultraviolet, EUV lithography machines requiring 13.5nm wavelength EUV light. This beam's quality—power, stability, bandwidth—directly determines whether the lithography machine can operate and howfine the circuits it can etch. EUV light sources areespecially arduous; they cannot be generated by directly exciting gases, but instead employ high-power carbon dioxide lasers, bombarding tens of thousands of falling liquid tin droplets per second with extreme frequency and precision, generating high-temperature plasma to radiate the required EUV light. This process involvesextreme challenges across numerousadvanced fields including plasma physics, precision fluid control, and materials science.
**Optical System**—the lithography machine's "soul." Comprising dozens of exceptionally precisemirrors with surface smoothness requirements reaching atomic levels (in EUV, since all materials strongly absorb 13.5nm light, multilayerfilm mirrors based on Bragg reflection principles must be used). This lens assembly's task is to demagnify and focus the light emitted by the source, through the circuit pattern on themask,finally projecting it accurately onto the silicon wafer coated with photoresist. The optical path may extend several meters, yetfinal imaging errors must be controlled within a few nanometers. This demandsnear-perfect lenses themselves; their materials, coatings, support structures, and thermal stability all represent thelimits of optical engineering.Numerical Aperture, NA is the key parameter measuring an optical system's light-gathering capability and resolution. Pursuing higher NAimplies greater lens curvature, more complex designs, and more stringent manufacturing processes.
**Wafer Stage System**—the lithography machine's "arm" and "stride." It carries and moves the silicon wafer (and mask), requiring nanometer-level precision and extremely high speeds for stepping and scanning motions during exposure. Dual-stage technology is standard in modern high-end lithography machines: while one stage exposes, the other simultaneously performs wafer handling, alignment, and measurement, dramatically boosting production efficiency. The stage's movement precision, stability, and speed directly determine the lithography machine'soverlay accuracy andthroughput. Behind this lies theextreme fusion ofultra-precision mechanical engineering,control theory,materials science, andvibration science.
These three systems interlocked like a precision gear set; aminor flaw in anylink could cause the entire machine's performance to collapse. And China, at the moment Xiuxiu decided to return, facedvast generational gaps across these three systems—especially in the mostcutting-edge EUVdomain—compared to thehighest levels represented by ASML. DUV lithography machines, though partially mastered, still relied on imports for stability, yield rates, and core components; EUV was even moremired in arduous exploration andkey problem tackling (key problem tackling)—light source power, optical lens manufacturing, vacuum environment control, defect detection... roadblockseverywhere.
Mr. Van der Veer could not comprehend, or perhaps was unwilling to comprehend, thisbond rooted inbloodline and cultural depth. In his view, Xiuxiu's choice was irrational—"politics" interfering with the purity of "science."
"Xiu," his tone acquired a barely perceptible chill, "think carefully. What you return to may not be an ideal environment supportingfrontier research. Resources, equipment, supply chains... even your academic freedom could be significantly diminished. Your years ofaccumulation andtalent might be wasted solving some... um... fundamental engineering issues."
"Vice President," Xiuxiu lifted her gaze, calmly meeting his, "what you say may be true. But precisely because there are 'fundamental engineering issues' to solve there, generational gaps to narrow, I need to return all the more. Mytalent andaccumulation, if they can only be used to add flowers to brocade, rather thansend charcoal in snowy need, that would be true waste."
She paused, enunciating word by word, her voice soft yet diamond-hard: "**Light should know no borders. It belongs to the cosmos, to all who yearn to explore. But the lithography machines that create, harness, and employ it to etch future chips do. And those whomanufacture anduse them, even more so.**"
In that moment, the office fell into briefstasis. Mr. Van der Veer looked at this slender,gentle-featured Eastern woman before him, yet seemed to see a silent, steadfast mountain range. He knew anyattempt to retain was futile.
Herthoughts withdrew from yesterday's confrontation. Xiuxiu's gaze refocused on the reality outside the window. She picked up the already-signed resignation letter on her desk; thepaper document carried a weight bothconclusive and inaugurative.
She beganorganizing her personal effects. Mosttechnical documents contained companyconfidential information and must remain. What she couldtake was only theknowledge,experience, and profound understanding of the lithography machine's entire system accumulated in her mind over years. She carefullyput away that abstract painting—gifted when she first joined by an old engineer who appreciated hertalent,symbolizingseekingorderlight paths withinchaos. She cast one last glance at the formulas and sketches on the whiteboard, reached out, and slowly, resolutely began erasing each mark.
White powdersifted down, like a period punctuating this career chapter. Those complex calculations, flashes ofinspiration, parameters refined throughcountless failures and optimizations would be sealed deep in memory, awaiting reactivation in another land, in another form.
A colleague knocked and entered—Hans, the German engineer who entered ASML alongside her. His expression wascomplex: incomprehension, regret, a faint trace of detachment.
"Xiu, really leaving?" Hans leaned against the doorframe, his tone subdued. "Because of those... political noises?"
Xiuxiu placed the last few personal notebooks into a cardboard box, shaking her head. "Not entirely, Hans. There is my home. Now home needs me; there are things that must be done, waiting for me to do them."