Photoresist Stripper Anji Microelectronics ICS8000 is a formulated liquid mixture supplied for removal of photoresist and organic post-etch residue from semiconductor wafer surfaces. The model designation ICS8000 identifies a proprietary solvent-amine system; exact composition is disclosed through the safety data sheet prepared under GB/T 16483-2008 and the Globally Harmonized System of Classification and Labelling of Chemicals. Published quantitative performance data for this specific formulation in peer-reviewed industrial literature is limited; process qualification therefore depends on the certificate of analysis and on-tool defect data. The product is handled as a moisture-sensitive and oxygen-sensitive liquid; closed-loop dispensing and nitrogen blanketing are normally specified to limit water uptake and oxidative darkening. Viscosity and density are verified at 25 °C using oscillating U-tube densitometry per ISO 12185:1996 and rotational viscometry per ISO 3219:1993. The product is typically packaged in fluoropolymer-lined drums or canisters fitted with 0.1 µm point-of-use filtration. Because batch-to-batch viscosity variation can shift diaphragm pump stroke volume on production coat/develop tracks, in-line mass flow control is preferred over volumetric metering. The material is not classified as an etchant; it acts through polymer swelling, dissolution, and residue lift-off. Specific gravity, flash point, boiling point, and vapor pressure for each batch are listed in the product certificate; no fixed public range is stated in the current revision of the manufacturer’s datasheet.

Process Variables Governing Removal Rate Uniformity in ICS8000

Removal rate uniformity for photoresist stripper ICS8000 is governed by temperature control, dispense mechanics, and wafer rotation. In single-wafer spray tools, the process chuck is typically held at 60 °C to 80 °C, while the stripper is dispensed through a swing-arm nozzle at a flow rate matched to resist thickness and ion dose. Published kinetic parameters for ICS8000 are not available; therefore the Arrhenius activation energy must be generated internally using oxide-masked silicon coupons coated with the target resist. The stripping endpoint is commonly monitored by optical emission or by visual inspection after DI water rinse. In immersion batch tools, bath temperature is controlled to ±1 °C because dissolution rate in solvent-amine systems can vary by 8 %/°C to 15 %/°C within the operating window. Recirculation flow through 10 µm to 50 µm PTFE filters removes particles but can shear the solvent; insufficient bath turnover creates a depleted boundary layer at the wafer surface and produces center-to-edge residue. On spray processors, rotation speed in the range 300 rpm to 800 rpm and nitrogen carrier pressure determine droplet impact energy; excess mechanical energy can cause foaming while low energy extends the time to clear resist from dense via arrays. Single-wafer spray equipment requires nozzle tip-to-wafer spacing to be held constant across the radius; a deviation of 2 mm changes local droplet density and can create a ring of under-stripped resist at the mid-radius. Exhaust balance in the process bowl must be adjusted to prevent solvent vapor from condensing on the chamber lid and dripping onto the wafer. In batch immersion, wafer boat material must be compatible with the stripper; polypropylene carriers may soften at operating temperature, while PTFE or stainless steel carriers are specified. The product is not blended on the fab floor; any dilution or additive adjustment invalidates the supplier’s compatibility qualification.

What Metal Compatibility Boundaries Apply to ICS8000?

Metal compatibility is evaluated by coupon immersion of blanket aluminum, copper, titanium nitride, and tungsten films in the stripper at process temperature. The corrosion inhibitor package in ICS8000 is formulated to suppress galvanic attack at the aluminum-copper interface during resist removal. Electrochemical acceptance testing typically follows ASTM G5-14 or ASTM G61-86, with potentiodynamic polarization used to determine the open-circuit potential and pitting potential. If the supplier’s blanket film etch rate limits are not publicly available, a conservative acceptance threshold for copper-compatible strippers is 5 Å/min; this value is not specific to ICS8000 and must be replaced by the manufacturer’s specification. Galvanic corrosion at aluminum-copper contacts is a known failure mode in solvent-based stripping; the electrochemical cell forms if the stripper bath contains chloride contaminants. Chloride is controlled by raw material specification and by monitoring the bath after repeated use; a chloride concentration exceeding 1 ppm is commonly considered actionable for copper-compatible strippers, but the ICS8000 limit is taken from the supplier’s analysis report. Residue left after stripping is not solely organic; fluorinated polymer residue from CF₄-based plasma etch can shield the metal surface and create local oxygen concentration cells. Stripper formulations that contain hydroxylamine or free fluoride may produce pitting on copper; therefore the ICS8000 corrosion package is qualified on patterned via chains with Kelvin resistance measurements before and after strip. The product should not be heated above the supplier-specified ceiling because corrosion inhibitors can volatilize and lose passivation efficiency. Titanium nitride and tungsten compatibility should be verified separately because tungsten plug recess can occur in oxidizing stripper baths. The use of an inhibitor package does not eliminate the need for dry-wafer transfer after rinse; residual water films can promote copper oxidation before the next process step.

For copper/low-k interconnect structures, post-etch residue contains organosilicate polymer, copper oxide, and fluorocarbon species. Photoresist stripper ICS8000 is evaluated for dielectric compatibility by measuring the change in dielectric constant of blanket low-k films after immersion or spray processing. A pass criterion often requires a k-value shift of less than 0.2 after 30 min of exposure at the maximum specified process temperature; the specific value for ICS8000 is taken from the supplier’s qualification report because published data for this configuration is limited. Low-k damage appears as carbon depletion in the SiOC network, detected by Fourier-transform infrared spectroscopy as a reduction in the Si-CH₃ peak near 1275 cm⁻¹ and an increase in silanol absorption near 3400 cm⁻¹. Strippers containing water can hydrolyze porous low-k and increase k-value; formulations with reduced water content or added surface tension modifiers are preferred for dielectrics with k ≤ 2.5. Porosity of low-k films is characterized by ellipsometric porosimetry before and after stripper exposure; a shift in open porosity of more than 3 % absolute is commonly considered process-relevant. In patterned structures, residue clearance from 65 nm and smaller vias is monitored by top-down SEM and cross-sectional TEM; incomplete residue removal creates contact resistance scatter that appears electrically as via chain yield loss. Post-strip defect inspection with brightfield and darkfield wafer scanners at sensitivities below 90 nm is used to detect residue and corrosion pitting; scan recipes must distinguish stripper residue from watermarks because both can appear as light scattering defects. The product’s differentiation from conventional NMP-based strippers is assessed by the absence of copper corrosion and by the post-strip defect density on patterned wafers, not by bulk resist dissolution rate alone.

When High-Dose Implant Crust Requires an Integrated Ash-Strip Sequence

After source-drain implant with doses above 1 × 10¹⁵ ions/cm², the resist surface forms a highly cross-linked carbonized crust that resists solvent penetration. For photoresist strippers in this class, direct crust removal without preceding plasma ash is generally not recommended; the ash step oxidizes the crust and leaves a smaller organic residue. The integrated sequence comprises oxygen or forming-gas plasma ash in a barrel or downstream asher, followed by liquid stripper treatment to dissolve the remaining resist and neutralize residual halogens. Process integration requires matching the ash over-strip time to the ICS8000 bath temperature; excessive ashing can dehydrate the residue and render it insoluble in the solvent, while insufficient ashing leaves the crust mechanically intact. Batch immersion processing after high-dose implant is performed with agitation and ultrasonic or megasonic energy in some flows; the manufacturer’s compatibility data should be consulted before applying megasonics because cavitation can accelerate metal corrosion at exposed contacts. A typical immersion time for solvent-amine strippers ranges from 10 min to 30 min at 70 °C to 80 °C; the exact ICS8000 process window is fixed by the uniformity test on monitor wafers. Control of residual halogen is important because chlorine and fluorine from implant species can form acids in subsequent thermal steps; liquid stripper neutralization is often combined with a dilute acid or alkaline rinse depending on the residue chemistry. The ICS8000 rinse sequence should be qualified with X-ray photoelectron spectroscopy to confirm that chlorine and fluorine surface concentrations are below the target for the gate stack. If megasonic energy is used, transducer frequency and power density are set to avoid pattern damage in high-aspect-ratio features; typical power density ranges from 0.5 W/cm² to 2.0 W/cm² for solvent bath cleaning. Ion implant photoresist removal is judged by light-point defect count, surface roughness, and residual carbon measured by X-ray photoelectron spectroscopy.

Rinse Architecture Determines Defect Density More Than Stripping Chemistry

Post-strip rinse with deionized water is required to remove dissolved resist and stripper residues. On single-wafer processors, a two-step rinse at 20 °C to 25 °C with a final nitrogen spin-dry at 1500 rpm to 2500 rpm reduces watermarks. In immersion tools, cascade rinsing with hot DI water at 55 °C to 65 °C is used because the rinse temperature must be close to the bath temperature to prevent thermal shock and residue precipitation. Filtration of the recirculated stripper is typically maintained with 0.05 µm to 0.2 µm polytetrafluoroethylene membrane cartridges; liquid particle counts are monitored with an optical particle counter calibrated to ISO 21501-4. Point-of-use filtration before dispense prevents filter-shed particles from reaching the wafer; the filter housing and membrane must be flushed for a defined volume before first wafer processing. Bath life is determined by the accumulation of dissolved resist, metal ions, and water; when dissolved resist loading exceeds a defined weight percent, the stripping rate drops and the residue re-deposition risk increases. The specific bath life limit for ICS8000 is expressed in the supplier’s maintenance procedure as a function of wafer area processed per liter, not by elapsed time alone. Replacement of the bath and filter elements is scheduled on the basis of particle count trend rather than fixed calendar days. The product’s viscosity at bath temperature influences the pressure drop across the filter; if the viscosity rises due to water absorption, the filter differential pressure increases and the pump may cavitate. Drum and canister residues must be segregated as organic solvent waste; local wastewater discharge limits for nitrogen compounds and trace metals apply.

A direct substitution of ICS8000 for hydroxylamine-based strippers in an existing fab process must be preceded by coupon-level corrosion testing and patterned-wafer defect evaluation. Hydroxylamine-containing formulations are effective at low temperature but are strongly reducing and can attack copper in the presence of dissolved oxygen; fluoride-containing semi-aqueous formulations remove silicon-containing residue rapidly but can etch silicon dioxide and low-k dielectrics if water content is not tightly controlled. The ICS8000 product is positioned to avoid free fluoride attack and to maintain copper passivation while retaining adequate residue clearance; comparative data should be generated on the target film stack because published data for this specific configuration is limited. Differences are measured by via chain yield, contact resistance stability, dielectric constant shift, and surface roughness after 1 h of exposure at the intended process temperature. Equipment change-out is not a drop-in substitution; filtration media, rinse protocol, and exhaust scrubber settings may require adjustment because the solvent vapor pressure and decomposition products differ from hydroxylamine formulations. The replacement of an NMP-based stripper with ICS8000 may require requalification of waste treatment because NMP and amine solvents have different biological oxygen demand and nitrogen loading profiles. In semiconductor wastewater neutralization, elevated organic nitrogen can increase total nitrogen discharge; the facility must compare the new waste stream against its discharge permit under GB 8978-1996 or local equivalent. For fabs operating under EC 1907/2006, the use is industrial and subject to exposure scenario conditions in the extended safety data sheet.

Incoming inspection of ICS8000 is organized around the methods listed in the following compliance matrix. The matrix does not replace the supplier’s certificate of analysis or the process-specific qualification report.