{"id":707,"date":"2026-06-01T05:34:46","date_gmt":"2026-06-01T05:34:46","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?p=707"},"modified":"2026-06-01T05:34:46","modified_gmt":"2026-06-01T05:34:46","slug":"planetary-gearbox-semiconductor-wafer-handling-cleanroom","status":"publish","type":"post","link":"https:\/\/planetary-gearboxes.com\/nl\/planetary-gearbox-semiconductor-wafer-handling-cleanroom\/","title":{"rendered":"Planetary Gearbox for Semiconductor Equipment \u2014 Cleanroom and Wafer Handling"},"content":{"rendered":"
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<\/p>\n

\"planetary<\/p>\n
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Semiconductor Application Guide \u00b7 ISO 14644 \u00b7 Outgassing \u00b7 Non-Magnetic \u00b7 Samsung \/ SK Hynix<\/div>\n

Planetary Gearbox for Semiconductor Equipment \u2014
\nCleanroom, Wafer Handling, and Low-Outgassing Design<\/h1>\n

Every planetary gearbox semiconductor equipment selection decision starts with one question standard catalogues cannot answer. A standard industrial planetary gearbox that performs flawlessly for ten years on a Korean packaging line will contaminate a wafer fab cleanroom within weeks \u2014 not because its precision is inadequate, but because its lubricant outgasses VOCs at 20\u00b0C that deposit on 300 mm silicon wafer surfaces, its steel housing sheds ferromagnetic particles that magnetise during transport, and its standard housing coating releases micro-particulates that exceed ISO Class 5 concentration limits. This guide covers every specification dimension that separates cleanroom-compatible gearboxes<\/strong> from standard industrial units.<\/p>\n

View EP-AFHK Ultra-Precision Series \u2192
\n<\/a><\/p>\n<\/div>\n<\/section>\n

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Korean Semiconductor Manufacturing \u2014 Why Gearbox Specifications Are Uniquely Demanding<\/h2>\n

Korea operates the world’s highest-density semiconductor manufacturing capacity. Samsung’s Pyeongtaek fab (P3 and P4 phases) and SK Hynix’s Cheongju M15X facility collectively produce the majority of the world’s DRAM and NAND flash memory. These facilities process 300 mm silicon wafers through 400\u2013600 photolithography, deposition, etch, and CMP process steps in cleanrooms maintained at ISO Class 3\u20135 (10\u2013100 particles \u22650.1 \u03bcm per cubic metre of air).<\/p>\n

The gearboxes used in this environment \u2014 in FOUP transport AGVs, wafer handler rotation axes, load port alignment stages, photolithography reticle stages, and CMP head rotation drives \u2014 are exposed to the same cleanroom specification as every other component. A gearbox that releases particles, outgasses chemicals, or generates magnetic fields that could interfere with alignment systems is not a “lower-quality” gearbox \u2014 it is simply a gearbox designed for a different environment, placed in the wrong one.<\/p>\n

\"Planar<\/p>\n

Understanding the planetary gearbox semiconductor cleanroom specification allows Korean equipment suppliers to the semiconductor industry to specify the correct gearbox configuration from the start \u2014 rather than discovering incompatibilities during customer acceptance testing, which is the most costly point at which to resolve a component specification error.<\/p>\n

<\/p>\n

\n\n\n\n\n\n\n\n\n
Korean Fab Zone<\/th>\nISO Class<\/th>\nMax particles \u22650.1\u03bcm per m\u00b3<\/th>\nTemp \/ Humidity<\/th>\nGearbox use<\/th>\n<\/tr>\n<\/thead>\n
Photolithography bay<\/td>\nISO 3<\/td>\n10<\/td>\n20\u00b0C \u00b10.1\u00b0C \/ 40% RH<\/td>\nReticle stage, wafer loader \u2014 most demanding<\/td>\n<\/tr>\n
Deposition \/ etch bays<\/td>\nISO 4\u20135<\/td>\n100\u20131,000<\/td>\n20\u201322\u00b0C \/ 40\u201350% RH<\/td>\nEquipment handlers, overhead transport<\/td>\n<\/tr>\n
CMP \/ packaging bays<\/td>\nISO 6\u20137<\/td>\n10,000\u2013100,000<\/td>\n20\u201323\u00b0C \/ 40\u201360% RH<\/td>\nFOUP transport, material handling AGV<\/td>\n<\/tr>\n
Fab support corridor<\/td>\nISO 8<\/td>\n3,520,000<\/td>\nAmbient \u00b12\u00b0C<\/td>\nStandard EP-AB acceptable in this zone<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

ISO 14644-1:2015 cleanliness classifications. Korean semiconductor fab zones from Samsung\/SK Hynix equipment specifications. All fab areas maintain approximately 20\u201322\u00b0C year-round \u2014 the EP-KF\/KH hypoid series 0\u00b0C minimum is not a concern for any indoor fab installation.<\/p>\n<\/section>\n

<\/p>\n

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Four Ways a Standard Gearbox Contaminates a Semiconductor Fab<\/h2>\n

Cleanroom incompatibility in standard gearboxes arises through four independent mechanisms. Each must be addressed separately \u2014 eliminating one does not address the others.<\/p>\n

\n
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\n
1<\/div>\n
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Lubricant outgassing \u2014 the invisible contamination<\/div>\n

Standard sealed greases use mineral oil or PAO (polyalphaolefin) base oils with amine- or calcium-based thickeners. At room temperature in a cleanroom, these compounds release volatile organic compounds (VOCs) through vapour pressure \u2014 a process called outgassing. The released VOCs are invisible at the molecular level, but they deposit on nearby surfaces including silicon wafer surfaces and reticle glass.<\/p>\n

Mechanism:<\/strong> At 20\u00b0C, a standard mineral-oil grease may have a vapour pressure of 10\u207b\u2074 to 10\u207b\u00b3 Pa. Deposition rate on nearby surfaces: approximately 0.1\u20131 ng\/cm\u00b2\/hour. On a 300 mm wafer positioned 500 mm from a contaminating gearbox, over a 24-hour continuous operation period, this deposits an organic film that alters the surface wettability and adhesion properties of the photoresist \u2014 causing defects in subsequent lithography steps.<\/p>\n

Solution:<\/strong> PFPE (perfluoropolyether) grease. Vapour pressure at 20\u00b0C: <10\u207b\u00b9\u2070 Pa \u2014 seven or more orders of magnitude lower than mineral oil. PFPE grease is chemically inert, non-reactive with process gases, and produces no measurable organic deposition on nearby surfaces. Korea Ever-Power EP series gearboxes with cleanroom-grade PFPE grease are available on special order \u2014 specify “semiconductor cleanroom PFPE lubricant” at time of order.<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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2<\/div>\n
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Particle generation from gear mesh wear debris<\/div>\n

Every planetary gearbox generates sub-micron metallic wear particles at the gear mesh contact zone \u2014 an unavoidable result of the sliding and rolling motion at the tooth interface. In industrial environments, these particles are retained inside the sealed housing by the grease structure. In a cleanroom gearbox, the concern is that any pathway through which particles can escape must be eliminated: the shaft seal must prevent particle migration along the shaft surface, and the housing must have no micro-gaps through which particle-laden air can be pumped by the gearbox’s thermal breathing cycle.<\/p>\n

Mechanism:<\/strong> As a gearbox heats from cold start to operating temperature, the air inside the housing expands and seeks to escape through the lowest-resistance path \u2014 typically along the shaft seal lip. On cooling, outside air (and any particles it contains) is drawn back in. This “breathing” effect can transport particles in both directions. Solution:<\/strong> Fully sealed housing with no thermal breathing path \u2014 achieved by eliminating breather vents and specifying FFKM (perfluoroelastomer) shaft seals that maintain tighter lip contact across the full operating temperature range than standard NBR or FKM seals.<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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3<\/div>\n
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Housing surface coating outgassing and particulation<\/div>\n

Standard industrial gearbox housings use oil-based or acrylic paint coatings that cure at room temperature. These coatings continue to release solvent residues (VOCs) for months after application and shed micro-particles as the coating surface weathers. In an ISO Class 3\u20135 cleanroom, even a small particle source can exceed the allowed particle concentration limit in the immediate vicinity of the gearbox.<\/p>\n

Solution:<\/strong> Bare anodised aluminium housing (no paint coating) or electroless nickel plating with zero VOC content and minimal particulation rate. Some Korean fab equipment suppliers use electropolished stainless steel housings for the most demanding ISO Class 3 applications. Korea Ever-Power can specify bare anodised housing on EP series gearboxes for cleanroom applications \u2014 specify at order time.<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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4<\/div>\n
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Ferromagnetic material and stray magnetic fields<\/div>\n

Standard gearbox components (housing, gears, shafts, planet carriers) are made from standard carbon or alloy steel \u2014 ferromagnetic materials with significant magnetic permeability. In most applications, this is irrelevant. In Korean MRAM (Magnetic Random Access Memory) fabrication areas and in the vicinity of electron beam lithography equipment, stray magnetic fields from ferromagnetic components cause alignment errors in the electron beam column and can alter the magnetic state of partially-fabricated MRAM cells.<\/p>\n

Mechanism:<\/strong> A standard steel gearbox housing has relative magnetic permeability \u03bc\u1d63 of 100\u20131,000 (ferromagnetic). At a distance of 300 mm, even the Earth’s ambient magnetic field is distorted by the housing \u2014 and any stray field from motor magnets or power cables coupling into the housing produces a time-varying field that can exceed the 10 nT field stability requirement in some EUV lithography systems. Solution:<\/strong> Austenitic stainless steel (SS316L, \u03bc\u1d63 \u2248 1.003) or aluminium (\u03bc\u1d63 \u2248 1.000006) housing construction eliminates the ferromagnetic concern. This is a special order requirement \u2014 confirm with Korea Ever-Power application engineering for your specific fab zone and equipment type.<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

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ISO 14644 Cleanroom Class \u2192 Gearbox Specification Requirements<\/h2>\n

Not every semiconductor fab zone requires the full cleanroom gearbox specification package. The requirements scale with cleanroom class \u2014 an ISO Class 7 material handling corridor has fundamentally different requirements from an ISO Class 3 photolithography bay. Over-specifying cleanroom features adds cost without functional benefit; under-specifying risks fab contamination events.<\/p>\n

\n\n\n\n\n\n\n\n\n
ISO Class<\/th>\nLubricant<\/th>\nShaft seal<\/th>\nHousing coating<\/th>\nNon-magnetic<\/th>\nKorea Ever-Power order note<\/th>\n<\/tr>\n<\/thead>\n
ISO 8 (support corridor)<\/td>\nStandard grease \u2713<\/td>\nStandard NBR \u2713<\/td>\nStandard paint \u2713<\/td>\nNot required<\/td>\nStandard EP-AB stock \u2014 no special order needed<\/td>\n<\/tr>\n
ISO 6\u20137 (CMP\/packaging)<\/td>\nPFPE preferred<\/td>\nFKM or FFKM<\/td>\nLow-VOC or anodised<\/td>\nConfirm per zone<\/td>\nSpecify “cleanroom grease + FKM seal” at order<\/td>\n<\/tr>\n
ISO 4\u20135 (deposition\/etch)<\/td>\nPFPE required<\/td>\nFFKM required<\/td>\nAnodised Al required<\/td>\nIf MRAM\/EB zone: yes<\/td>\nFull cleanroom spec order; 2\u20133 week lead time<\/td>\n<\/tr>\n
ISO 3 (EUV litho bay)<\/td>\nPFPE required<\/td>\nFFKM required<\/td>\nElectropolished SS316L<\/td>\nRequired<\/td>\nCustom engineering required \u2014 engage Korea Ever-Power application team early in design phase<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

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Critical ordering instruction: <\/strong>
\nAll cleanroom-specific options \u2014 PFPE grease, FFKM seal, anodised housing, non-magnetic construction \u2014 must be specified at the time of ordering. Standard EP series gearboxes ship with standard mineral\/PAO grease, NBR seals, and painted housing. No field conversion is possible. If you receive a standard unit and then discover the fab zone requires PFPE lubricant, the gearbox must be returned and replaced with a cleanroom-specified unit. Lead time for cleanroom options is 2\u20134 weeks; plan accordingly in the equipment procurement schedule.<\/span><\/div>\n<\/section>\n

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Wafer Handler Rotation Axis \u2014 Precision Requirements and Series Selection<\/h2>\n

Planetary gearbox semiconductor wafer handler drives require precision that exceeds most industrial servo applications. Robotic wafer handlers \u2014 the equipment that transfers 300 mm silicon wafers between FOUPs, process chambers, and aligners \u2014 use two rotation axes: a theta (\u03b8) rotation axis that rotates the entire arm assembly to align with target slots, and an extension axis that extends and retracts the end effector radially. The theta axis positioning accuracy determines whether the wafer is placed within the end effector’s centre tolerance; the extension axis determines radial position accuracy.<\/p>\n

\"pls-high-precision-planetary-gearbox-application\"<\/p>\n

The critical positioning requirement for the theta axis: the wafer centre must be placed within \u00b10.5 mm of the target position at the nominal 300 mm wafer radius (150 mm from wafer centre). This requires the theta axis angular error to be:<\/p>\n

\n

THETA AXIS BACKLASH REQUIREMENT \u2014 WAFER HANDLER<\/p>\n

Required: position error \u2264 \u00b10.5mm at r = 300mm arm radius<\/p>\n

Angular error \u03b8_max = \u0394x \/ r = 0.5 \/ 300 = 0.00167 rad
\n= 0.00167 \u00d7 (180 \u00d7 60 \/ \u03c0) = 5.7 arcmin maximum<\/span><\/p>\n

Gearbox backlash budget (40% of total error):
\n\u03b8_gearbox \u2264 5.7 \u00d7 0.40 = 2.3 arcmin<\/p>\n

\u2192 Requires backlash \u2264 2.3 arcmin at output shaft
\n\u2192 P1 (\u22643′) is marginal \u2014 may exceed budget at worst case
\n\u2192 P0 (\u22641′) provides 2.3\u00d7 margin \u2014 correct specification
\n\u2192 EP-AFH (\u22641′ standard) eliminates grade specification step<\/p><\/div>\n<\/div>\n

For Korean wafer handler OEMs, the EP-AFH ultra-precision series<\/a> is the standard recommendation for the theta axis. Every EP-AFH unit ships with \u22641 arcmin as its standard specification \u2014 no grade code selection, no unit-to-unit measurement variability within the grade band. The delivery certificate confirms the measured value on each unit. For the extension (radial) axis, the precision requirement is lower (\u00b11 mm tolerance at the effector tip) and P0 or P1 is appropriate depending on the arm geometry.<\/p>\n

Temperature stability and thermal positioning drift: <\/strong>
\nKorean wafer fab cleanrooms maintain 20\u00b0C \u00b10.1\u00b0C temperature stability. This precision temperature control is maintained specifically to prevent thermal expansion of equipment from causing positioning drift. A cleanroom gearbox in a thermally stable environment achieves positioning repeatability limited by backlash and encoder resolution \u2014 not by thermal expansion. The highly stable cleanroom temperature is itself a design enabler: gearbox thermal drift, which is a significant concern in standard industrial applications, is essentially zero in a properly controlled fab environment.<\/span><\/div>\n<\/section>\n

<\/p>\n

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FOUP Transport AGV \u2014 Drive Wheel Specification for Fab Floor Operation<\/h2>\n

Front Opening Unified Pod (FOUP) transport within Korean semiconductor fabs uses overhead hoist transport (OHT) systems on ceiling rails as the primary means for fab-to-bay FOUP movement, and floor-level AGVs for bay-to-equipment transfer at lower-traffic zones. The floor-level AGV drive wheel gearboxes operate in the same cleanroom environment as the process equipment.<\/p>\n

FOUP transport AGV gearbox requirements combine the cleanroom specifications from modules 2\u20133 with the AGV-specific requirements from Art12: differential drive speed synchronisation (matched pair, \u22640.01% ratio variation certificate), low operating noise (acoustic vibration that could disturb nearby lithography alignment in adjacent bays must be below 55 dB(A) at the bay boundary), and zero-maintenance sealed construction.<\/p>\n

The EP-KF\/KH hypoid series<\/a> is appropriate for Korean fab AGV drive wheels \u2014 the fab environment maintains 20\u00b0C constant, well above the KF\/KH 0\u00b0C minimum operating temperature. The hypoid gear contact geometry produces approximately 6\u20138 dB(A) lower operating noise than standard planetary at equivalent torque, which is meaningful in the acoustically-sensitive fab environment. For FOUP transport AGV, specify the cleanroom lubricant option (PFPE) and FFKM shaft seals in addition to the matched-pair speed synchronisation certificate.<\/p>\n

\"Korea<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Semiconductor Equipment Drive<\/th>\nBacklash req.<\/th>\nCleanroom spec<\/th>\nKorea Ever-Power Series<\/th>\n<\/tr>\n<\/thead>\n
Wafer handler \u03b8-axis (ISO 4\u20135)<\/td>\n\u22641 arcmin<\/td>\nPFPE + FFKM + anodised<\/td>\nEP-AFH<\/a> + cleanroom spec<\/td>\n<\/tr>\n
Wafer handler extension axis (ISO 4\u20135)<\/td>\n\u22643 boogminuten<\/td>\nPFPE + FFKM<\/td>\nEP-AB P0\/P1<\/a> + cleanroom spec<\/td>\n<\/tr>\n
FOUP AGV drive wheel (ISO 6\u20137)<\/td>\nRatio match \u22640.01%<\/td>\nPFPE + FKM seal<\/td>\nEP-KF matched pair<\/a> + cleanroom spec<\/td>\n<\/tr>\n
CMP head rotation (ISO 6)<\/td>\n\u22641 arcmin<\/td>\nPFPE + FFKM + anodised<\/td>\nEP-AFH + cleanroom spec<\/td>\n<\/tr>\n
Load port alignment stage (ISO 5)<\/td>\n\u22641 arcmin<\/td>\nPFPE + FFKM + anodised<\/td>\nEP-ABR P0<\/a> or EP-AFH + cleanroom spec<\/td>\n<\/tr>\n
Fab support \/ utility drives (ISO 8)<\/td>\nP2 adequate<\/td>\nStandard stock<\/td>\nEP-AB P2 standard \u2014 no special order<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n

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MRAM Fabrication and EUV Lithography \u2014 Non-Magnetic Construction Specification<\/h2>\n

Magnetic RAM (MRAM) and spin-transfer torque RAM (STT-RAM) fabrication \u2014 an emerging advanced process technology at Samsung and SK Hynix \u2014 requires controlled magnetic environments throughout the deposition steps that define the magnetic tunnel junction (MTJ) layer stack. The coercivity of these layers is in the range of 5\u201350 Oersted; a stray magnetic field of even 1 Oersted from nearby equipment during the deposition step can alter the intended magnetic moment orientation in the MTJ layer.<\/p>\n

\"Planerary<\/p>\n

EUV (Extreme Ultraviolet) lithography systems \u2014 deployed at Samsung’s Hwaseong and Pyeongtaek fabs since 2019 \u2014 use electron-optical columns that are sensitive to stray magnetic fields at the sub-nanotesla level. A standard steel gearbox at 500 mm distance from the electron optical axis produces a stray field of approximately 100\u2013500 nT \u2014 two to four orders of magnitude above the system’s field stability requirement.<\/p>\n

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Magnetic permeability comparison \u2014 gearbox housing materials<\/div>\n
\n
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Standard carbon steel (ferromagnetic)<\/span>
\n\u03bc\u1d63 \u2248 100\u20131,000 \u2014 NOT for magnetic-sensitive zones<\/span><\/div>\n
\n
<\/div>\n<\/div>\n<\/div>\n
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Alloy steel (bearing steel)<\/span>
\n\u03bc\u1d63 \u2248 50\u2013200 \u2014 NOT for magnetic-sensitive zones<\/span><\/div>\n
\n
<\/div>\n<\/div>\n<\/div>\n
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Austenitic SS316L (non-magnetic stainless)<\/span>
\n\u03bc\u1d63 \u2248 1.003 \u2014 acceptable for most fab zones<\/span><\/div>\n
\n
<\/div>\n<\/div>\n<\/div>\n
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6061-T6 Aluminium<\/span>
\n\u03bc\u1d63 \u2248 1.000006 \u2014 negligible magnetic signature<\/span><\/div>\n
\n
<\/div>\n<\/div>\n<\/div>\n<\/div>\n

Relative magnetic permeability \u03bc\u1d63. Lower value = lower magnetic signature. Standard steel gearboxes produce stray fields approximately 1,000\u00d7 higher than aluminium-housed equivalents at the same distance.<\/p>\n<\/div>\n

For Korean equipment suppliers working in MRAM and EUV zones, including those designing compact staging systems with the EP-ADS compact series<\/a>, Korea Ever-Power EP series gearboxes can be specified with aluminium housing variants for both housing and planet carrier components. Note that the internal steel gear elements (planet gears, ring gear, sun gear) remain steel \u2014 this is unavoidable for precision gear manufacture. The steel gear elements produce a much smaller magnetic signature than the housing because they rotate at speed (reducing net static field contribution) and are substantially shielded by the outer housing. Full non-magnetic construction (including ceramic or titanium gear elements) is a custom engineering exercise beyond standard catalogue products from any manufacturer.<\/p>\n<\/section>\n

<\/p>\n

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Samsung and SK Hynix Supply Chain \u2014 Documentation Requirements for Equipment Qualification<\/h2>\n

Korean semiconductor equipment suppliers bidding to Samsung (Pyeongtaek, Hwaseong, Giheung) and SK Hynix (Cheongju, Icheon) must qualify their equipment through a multi-stage vendor acceptance process. Component-level documentation for drive components \u2014 including gearboxes \u2014 is typically required at the IQ (Installation Qualification) stage. The required document package varies by process zone cleanroom class and by the equipment type, but a standard package for precision drive components in ISO Class 4\u20135 zones includes the following items.<\/p>\n

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\u2460 Cleanroom material certification<\/div>\n

Manufacturer’s written declaration that all materials (housing, seals, lubricant) meet the fab’s material specification. For PFPE lubricant: include PFPE grade and supplier name. For FFKM seals: confirm fluorocarbon polymer specification. Korea Ever-Power provides this as a Korean-language written declaration.<\/p>\n<\/div>\n

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\u2461 Outgassing test data<\/div>\n

ASTM E1603 or equivalent outgassing test results for the lubricant and seal materials at 20\u201325\u00b0C. Shows total mass loss (TML) and collected volatile condensable material (CVCM). For PFPE grease, these values are typically <0.01% TML and <0.001% CVCM \u2014 well within standard fab limits.<\/p>\n<\/div>\n

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\u2462 Backlash measurement certificate<\/div>\n

Unit-specific measured backlash value (not just grade conformance statement). Korea Ever-Power provides this for all EP-AFH units and for EP-AB\/AF on P0 and P1 grades. Required for IQ documentation of positioning-critical drive axes.<\/p>\n<\/div>\n

\n
\u2463 RoHS and REACH compliance declaration<\/div>\n

Written confirmation that the gearbox does not contain prohibited substances under EU RoHS 2 (2011\/65\/EU recast) and REACH (EC 1907\/2006) SVHC lists. Required for equipment sold to multinational fab operators. Korea Ever-Power provides this as a standard document with cleanroom orders.<\/p>\n<\/div>\n

\n
\u2464 Dimensional drawing (PDF, Korean + English)<\/div>\n

Full dimensional drawing with toleranced dimensions for installation qualification. Required for IQ\/OQ protocol documentation. Korea Ever-Power provides this within 3 business days of order placement for any EP series model.<\/p>\n<\/div>\n

\n
\u2465 Matched pair ratio certificate (AGV only)<\/div>\n

For differential-drive FOUP AGV: ratio variation certificate for both drive wheel gearboxes, confirming \u22640.01% ratio difference between the pair. Korea Ever-Power provides this as a standard option when matched-pair AGV orders are specified.<\/p>\n<\/div>\n<\/div>\n

Procurement timing for Korean fab equipment projects: <\/strong>
\nSamsung and SK Hynix equipment qualification cycles typically run 6\u201312 months from equipment design freeze to fab acceptance. The gearbox documentation package is required at IQ stage \u2014 typically 4\u20136 months into the qualification cycle. For cleanroom-specified gearboxes (PFPE + FFKM, 2\u20134 week lead time), order placement should occur no later than 10 weeks before IQ documentation is required. Contact Korea Ever-Power at the design phase \u2014 not at the procurement phase \u2014 to confirm document availability and lead time for your specific fab zone and cleanroom class.<\/span><\/div>\n<\/section>\n

<\/p>\n

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Outgassing Budget Calculation \u2014 How to Determine Whether Standard or PFPE Grease Is Required<\/h2>\n

The decision between standard sealed grease and PFPE cleanroom lubricant depends on the outgassing load the gearbox contributes to the cleanroom air and its proximity to exposed wafer surfaces. The following calculation approach allows Korean equipment suppliers to make this decision quantitatively rather than by a conservative default that may add unnecessary cost.<\/p>\n

\n

OUTGASSING CONTAMINATION BUDGET \u2014 SIMPLIFIED MODEL<\/p>\n

Deposition rate on wafer D (ng\/cm\u00b2\/hr) from a single gearbox:<\/p>\n

D \u2248 P_vap \u00d7 M_grease \u00d7 k_geom \/ (R \u00d7 T)<\/p>\n

where:
\nP_vap = vapour pressure of lubricant base oil at 20\u00b0C (Pa)
\nM_grease = exposed grease surface area (cm\u00b2)
\nk_geom = geometric factor (depends on distance and angle, ~10\u207b\u2075 to 10\u207b\u00b3)
\nR, T = gas constant, temperature<\/p>\n

Mineral oil PAO (standard): P_vap \u2248 10\u207b\u00b3 Pa
\n\u2192 D \u2248 0.05\u20130.5 ng\/cm\u00b2\/hr at 300mm distance
\n\u2192 Over 24 hrs: 1.2\u201312 ng\/cm\u00b2 accumulation on wafer \u2190 FAILS ISO 5<\/p>\n

PFPE (cleanroom grade): P_vap \u2248 10\u207b\u00b9\u2070 Pa
\n\u2192 D < 10\u207b\u2077 ng\/cm\u00b2\/hr \u2014 7 orders of magnitude lower
\n\u2192 Unmeasurable by standard analytical methods \u2713<\/p><\/div>\n<\/div>\n

The calculation shows why PFPE is required and not merely preferred for any gearbox within line-of-sight of exposed wafers: standard grease vapour pressure is seven orders of magnitude higher than PFPE. No geometric factor or distance arrangement compensates for this fundamental difference. For any gearbox in ISO Class 3\u20136 zones where wafers may be exposed to the atmosphere, PFPE grease is a binary requirement, not a preference.<\/p>\n

\"planetary<\/p>\n

Where standard grease is acceptable in a semiconductor facility: <\/strong>
\nGearboxes installed in ISO Class 8 or lower areas (fab support corridors, utility rooms, equipment sub-floors) where wafers are never present do not require PFPE lubricant. Standard EP-AB or EP-BPG series with standard grease is the correct and most cost-effective specification for these zones. The PFPE premium (typically 30\u201350% higher unit cost) is only justified when the gearbox is in a zone where wafer exposure is possible. Applying cleanroom specification to all gearboxes in a fab facility, regardless of zone, unnecessarily increases BOM cost without functional benefit.<\/span><\/div>\n<\/section>\n

<\/p>\n

\n

Frequently Asked Questions \u2014 Planetary Gearboxes in Korean Semiconductor Equipment<\/h2>\n
\n
\n

Q<\/span>
\nOur Korean equipment customer (a fab equipment OEM supplying Samsung) requires a “particle-free” gearbox specification. What exactly does this mean in practice?<\/h3>\n

“Particle-free” in Korean fab procurement language typically means the gearbox must not shed particles above a specified size and count rate into the cleanroom atmosphere \u2014 not that it generates literally zero particles. The practical specification is usually expressed as a maximum particle generation rate at a specified distance and air flow condition, or as a material compatibility statement that the housing and seals will not shed particles above 0.1 \u03bcm size at a rate exceeding the cleanroom’s particle concentration budget for that installation. Korea Ever-Power addresses this through: (1) PFPE lubricant with sealed construction that prevents grease particle migration, (2) FFKM shaft seals that maintain positive containment across the operating temperature range, and (3) anodised aluminium housing that does not shed paint particles. A full particle generation test at the system level (gearbox installed in equipment, operating under cleanroom conditions) is typically conducted by the Korean equipment OEM, not by the gearbox supplier.<\/p>\n<\/div>\n

\n

Q<\/span>
\nWe are designing a Korean wafer fab CMP (Chemical Mechanical Planarisation) head rotation drive. What is the specific gearbox configuration?<\/h3>\n

A CMP head rotation drive positions the polishing head over the platen and rotates it during the polishing process. The drive requirement: moderate speed (30\u2013150 rpm), moderate torque (50\u2013300 N\u00b7m depending on head size and slurry type), \u22641 arcmin positioning for head index positioning, and cleanroom compatibility (the head operates over exposed wafer surfaces during polishing). The EP-AFH series is the standard recommendation \u2014 \u22641 arcmin standard specification, compact sealed construction, available with PFPE grease and FFKM seals for ISO Class 5\u20136 CMP bay requirements. For the rotation axis specifically, the EP-AFH inline series is preferred over right-angle configurations because the compact axial length reduces the moment arm that the head weight imposes on the gearbox output bearing.<\/p>\n<\/div>\n

\n

Q<\/span>
\nOur current gearbox uses standard sealed grease and has been in a Korean fab for 18 months without a noted contamination event. Do we need to switch to PFPE?<\/h3>\n

The absence of a detected contamination event does not confirm absence of contamination \u2014 cleanroom chemical contamination from gearbox outgassing is typically detected months after the contaminating event through yield analysis, not in real-time. A fab that achieves 95% photolithography yield may be losing 2\u20133% yield to organic surface contamination without tracing it to a specific source. If your gearbox is in an ISO Class 5 or better zone within 1\u20132 metres of exposed wafer surfaces, the outgassing calculation in Module 8 applies \u2014 the deposition rate from standard mineral oil grease is physically measurable and above cleanroom limits. Whether this deposition rate has been traced in your specific installation depends on the fab’s yield tracking system. Korea Ever-Power strongly recommends PFPE lubricant for any gearbox in ISO Class 5 or better zones near exposed wafers, regardless of whether a contamination event has been formally identified.<\/p>\n<\/div>\n

\n

Q<\/span>
\nFor Korean agricultural automation equipment that shares a facility with a semiconductor support zone, does cleanroom gearbox specification apply?<\/h3>\n

No \u2014 agricultural automation equipment and semiconductor facility automation are entirely separate application categories. Korean agricultural processing facilities (grain, vegetable, food processing) do not have ISO 14644 cleanroom requirements. The gearbox specification for Korean agricultural automation follows the food-processing hygiene requirements described in Art9 (IP67, KFDA compliance, sealed grease) rather than semiconductor cleanroom specifications. If a Korean facility combines agricultural processing and semiconductor packaging (for example, a specialty film or packaging supplier to a semiconductor fab), the appropriate specification for each zone follows that zone’s actual requirements \u2014 agricultural processing areas use food-safe gearboxes, and if any zone within the facility is designated to semiconductor cleanroom standard, that zone’s gearboxes follow ISO 14644 requirements. For multi-output power distribution to agricultural processing heads, agricultural bevel gearboxes<\/a> distributing from an EP planetary output to individual processing heads are appropriate in the non-cleanroom zones of such facilities.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Specify Your Semiconductor Equipment Gearboxes with Korea Ever-Power<\/h2>\n

Korea Ever-Power provides cleanroom-specified EP series gearboxes with PFPE lubricant, FFKM seals, anodised housing, and the full Samsung\/SK Hynix IQ documentation package \u2014 in Korean, with 2\u20134 week lead time. Engage at the design phase for best results.<\/p>\n

EP-AFH Ultra-Precision (Wafer Handler) \u2192
\n<\/a>
\nEP-KF\/KH Low-Noise (Fab AGV) \u2192
\n<\/a><\/div>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"

Semiconductor Application Guide \u00b7 ISO 14644 \u00b7 Outgassing \u00b7 Non-Magnetic \u00b7 Samsung \/ SK Hynix Planetary Gearbox for Semiconductor Equipment \u2014 Cleanroom, Wafer Handling, and Low-Outgassing Design Every planetary gearbox semiconductor equipment selection decision starts with one question standard catalogues cannot answer. A standard industrial planetary gearbox that performs flawlessly for ten years on a […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[965],"tags":[],"class_list":["post-707","post","type-post","status-publish","format-standard","hentry","category-application-and-technical-guid"],"_links":{"self":[{"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/posts\/707","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/comments?post=707"}],"version-history":[{"count":1,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/posts\/707\/revisions"}],"predecessor-version":[{"id":708,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/posts\/707\/revisions\/708"}],"wp:attachment":[{"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/media?parent=707"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/categories?post=707"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/nl\/wp-json\/wp\/v2\/tags?post=707"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}