When billions of transistors are packed into a chip no larger than a fingernail, few people ask: how were these circuit patterns, smaller than bacteria, originally "drawn"? The answer lies behind a seemingly ordinary piece of quartz glass—the photomask, a critical component known in the industry as the "semiconductor master template," which defines chip performance limits with nanometer-level precision.
**Three Centuries of Photomask Evolution**
Tracing the history of photomasks reveals an evolution story that mirrors the precision race in microscopic manufacturing. In the late 18th century, Frenchman Joseph Nicéphore Niépce created the world's first "photomask" using a bitumen-coated tin plate, capturing outdoor scenes on metal through sunlight exposure—a primitive imaging logic strikingly similar to today's semiconductor photomasks. The difference lies in scale: while the "pixels" of that era were millimeter-sized color blocks, today's have shrunk to 0.5 nanometers, equivalent to the precision control of scaling Earth down to ping-pong ball size.
In the late 1990s, as semiconductors entered the deep submicron era, photomask technology underwent its most dramatic transformation. KrF (248nm) lithography required photomask linewidths of 180nm, necessitating detection of defects as small as 50nm in diameter—like finding a speck of dust on a standard football field.
To meet these challenges, photomask manufacturing introduced Atomic Layer Deposition (ALD) technology, achieving chromium layer thickness control within ±0.1nm ranges, while developing laser repair systems using Focused Ion Beam (FIB) to precisely remove defects with 10nm-level repair accuracy.
Modern photomasks appear structurally simple: circuit patterns etched in chromium layers on high-purity quartz glass. However, actual manufacturing requires over 30 processing steps. Photomask substrates produced by Japan's Shin-Etsu Chemical maintain flatness errors within 0.3 nanometers per square centimeter.
In Samsung's 3nm GAA process launched in 2024, photomask technology achieved a crucial breakthrough: using Self-Aligned Quadruple Patterning (SAQP) technology, photomask sets created FinFET structures with 7nm spacing through four overlay exposures, despite limited physical resolution constraints. This resembles using four different angle negatives to create stereoscopic images on the same photographic paper, except here the "paper" is single-crystal silicon and the "image" consists of conductive nanostructures.
**The Industry's Critical Bottleneck**
Lithography represents one of the core steps in semiconductor device manufacturing, accounting for approximately one-third of total silicon wafer manufacturing costs and 40-60% of processing time. Photomasks play an irreplaceable role as "projection templates" in this process.
The workflow is extremely precise and complex. Specific light sources emit light—248nm KrF (krypton fluoride) excimer lasers are commonly used for 90nm to 0.25μm process nodes, while 193nm ArF (argon fluoride) excimer lasers support processes from 65nm down to current advanced 3nm nodes. Light passes through transparent regions of the photomask, where transparent and opaque areas are precisely defined by chromium layers and other materials, projecting carefully designed circuit patterns onto photoresist-coated wafer surfaces through exposure.
During exposure, photoresist undergoes photochemical reactions upon absorbing photon energy. For positive photoresist, exposed areas show increased solubility in developer solutions; negative photoresist behaves oppositely, with unexposed areas dissolving in developer. After development, wafer surfaces form patterns consistent with the photomask. Subsequently, etching processes like plasma etching use high-energy ion beams to bombard wafers, transferring developed photoresist patterns to specific material layers on wafers, removing unwanted material portions while leaving desired circuit structures.
Notably, photomask patterns are typically 4x larger than circuit designs, facilitating more precise processing and correction during photomask fabrication. Through advanced projection systems in lithography machines, featuring multiple high-precision lens groups, photomask patterns are reduced to 1/4 size when projected onto wafers. This reduction operation, based on optical imaging principles, not only improves resolution—theoretically proportional to exposure wavelength and inversely proportional to projection system numerical aperture—but also reduces manufacturing errors by significantly minimizing tiny deviations at pattern edges during the reduction process.
Photomasks function like projector "slides," using light projection to clearly map patterns onto "screens"—the wafers. Unlike ordinary slides, photomask manufacturing requires over 30 processes, from selecting high-purity quartz glass substrates (like those from Shin-Etsu Chemical with flatness errors under 0.3 nanometers per square centimeter) to precise etching of chromium opaque layers and electron beam or laser direct-write pattern creation. Each step demands strict precision and environmental cleanliness requirements, making photomasks true "bottlenecks" in semiconductor manufacturing that determine chip manufacturing precision and performance.
**Who Controls Photomask Discourse?**
Mastering high-end photomask technology, especially EUV photomask core technology and manufacturing capabilities, has become key to determining advanced chip manufacturing discourse power. Currently, this field's competitive landscape is highly concentrated, with few companies possessing cutting-edge technology firmly controlling critical industry chain nodes.
Examining the global photomask industry chain reveals a clear "pyramid" structure of discourse power distribution. The apex consists of Japanese, American, and some European companies occupying absolute dominant positions in high-end photomask manufacturing, core material supply, and advanced inspection equipment.
American company Photronics, as a leading global independent third-party photomask manufacturer, possesses deep technical expertise in photomask manufacturing across semiconductors, flat panel displays, and other fields. Founded in 1969, through continuous R&D investment and technological innovation, Photronics has mastered a series of advanced photomask manufacturing technologies. In Optical Proximity Correction (OPC) technology, Photronics optimizes photomask patterns through precise algorithms and advanced software tools to compensate for optical distortions during lithography processes, thereby improving chip manufacturing precision and yield rates.
Japan's advantages in the photomask industry are even more significant, not only in the number of high-end photomask manufacturing companies but also throughout the entire photomask manufacturing value chain. Beyond Toppan and DNP's leadership in high-end photomask manufacturing, Japanese companies also lead globally in photomask substrates, photoresist, and other critical materials, as well as photomask manufacturing equipment. Hoya and Shin-Etsu Chemical are the world's two largest suppliers, with combined market share exceeding 90%.
Hoya's photomask substrates feature extremely high flatness and optical properties, with advanced melting and processing technologies ensuring substrate performance stability under various environmental conditions, providing solid foundations for high-end photomask manufacturing. Shin-Etsu Chemical possesses unique technical advantages in high-purity quartz material production, with excellent performance in impurity content control and thermal stability, widely used in EUV photomasks and other high-end products.
In photoresist, JSR and Tokyo Ohka Kogyo (TOK) occupy major shares of the global semiconductor photoresist market. As critical materials in photomask manufacturing and chip lithography processes, photoresist performance directly affects photomask pattern transfer accuracy and chip manufacturing quality. Through long-term R&D investment and technological innovation, Japanese companies have developed a series of high-performance photoresist products meeting different process node requirements. For example, JSR's ArF photoresist exhibits excellent performance in resolution, sensitivity, and etch resistance, widely used in 14nm and below advanced process chip manufacturing.
Historically, China's mainland photomask industry has held a relatively weak position in the global value chain. Before 2020, while domestic photomask manufacturers were numerous, overall technical levels were low. The then-famous "three brothers"—Qingyi Photovoltaic, Luwei Optoelectronics, and Lontu Photomask—mostly concentrated their process capabilities between 0.25-0.5 micrometers, with Central Micro Mask Electronics slightly better at 0.13 micrometers.
In recent years, with high national attention to the semiconductor industry and strong policy support, domestic photomasks have entered a golden period of rapid development. Lontu Photomask entered the semiconductor mask business in 2010 and, through years of technical breakthroughs, improved process nodes from 1μm to 130nm. By the end of 2023, Lontu Photomask successfully passed review, planning to raise funds for high-end semiconductor chip mask manufacturing bases and other projects, accelerating 130nm and below process photomask domestication.
The company continuously introduces equipment and conducts technical research in high-precision semiconductor masks, mastering multiple independently developed core technologies including pattern compensation, precise alignment marking, lithography process control, exposure fine control, and defect repair and foreign object removal technologies, covering CAM, lithography, and inspection processes. Simultaneously, active technology layout and reserves include electron beam lithography and PSM phase-shift mask technologies, forming certain technical achievements.
Currently, Lontu Photomask has achieved 130nm process node semiconductor mask mass production with ±20nm CD precision and overlay accuracy. Its technical strength and process capabilities lead among domestic third-party semiconductor mask manufacturers. Products have been certified by multiple renowned domestic wafer manufacturers including SMIC, Silan Microelectronics, Advanced Semiconductor Manufacturing Corporation, Nuvoton Technology, BYD Semiconductor, Liwang Microelectronics, Yandong Microelectronics, YuanXin Semiconductor, Yangtze Advanced Materials, and Yangjie Electronic Technology.
Qingyi Photovoltaic continues breaking through as one of China's largest domestic photomask suppliers, consistently investing in semiconductor photomask R&D with products gradually advancing from low-mid to mid-high end. Through cooperation with domestic research institutions and advanced talent introduction, Qingyi Photovoltaic has achieved important progress in key photomask manufacturing technologies, developing proprietary detection algorithms and repair processes for photomask defect detection and repair, effectively improving photomask product quality and yield rates. Its products not only steadily increase domestic market share but also begin entering international markets, competing with international manufacturers and exporting to semiconductor-developed countries including South Korea and Japan.
Luwei Optoelectronics has also achieved notable results, realizing 250nm process node semiconductor mask mass production, mastering 180nm/150nm node core technologies with products widely applied across multiple fields, providing strong support for China's domestic semiconductor industry.
**Conclusion**
Photomasks, these small glass pieces, ultimately represent a competition about "doing things meticulously." From using bitumen tin plates to print landscapes centuries ago to drawing circuits at nanometer scales today, people constantly explore how to make patterns more precise and smaller. Leading international manufacturers simply push every detail to extremes—substrates must be flat with virtually no errors, materials must be pure beyond reproach.
These tasks are now being pursued step-by-step by domestic manufacturers. While they may not yet reach the pinnacle, each step is solid. Lontu Photomask's stable 130nm photomask mass production, Qingyi Photovoltaic's proprietary defect repair technology, and Luwei Optoelectronics' reliable processes in mature fields all represent visible progress.
No grand narratives are needed—just refining and perfecting existing technologies to ensure downstream manufacturers can use them confidently and smoothly. Perhaps in the future, nobody will specifically inquire about photomask manufacturers, just as nobody today questions pencil makers. However, these gradually polished precisions and accumulated experiences will eventually become confidence—proving that in this industry, we can do what needs doing well, keep pace, and even gradually forge our own path. That's enough.