Particle Count Certification
Comprehensive particle count inspection and certification — laser surface scanning down to 0.09μm, full wafer defect maps, size distribution analysis, and SEMI M52/M53 compliant reporting in ISO Class 1 cleanroom.
Overview
Particle contamination on wafer surfaces is arguably the single largest cause of yield loss in semiconductor manufacturing. A single particle ≥ 50% of the minimum feature size can cause a killer defect — bridging adjacent lines, blocking an etch, or creating a void in a deposited film. As device dimensions shrink below 10nm, the critical particle size that constitutes a "killer defect" has decreased proportionally, now extending well below 0.1μm for advanced logic and memory devices.
GINECHIP's particle count certification service provides KLA-Tencor Surfscan-based inspection and certification of particle levels on bare and blanket-film wafers. With detection sensitivity down to 0.09μm PSL equivalent, full-wafer defect mapping, particle size distribution analysis, and comprehensive statistical reporting — our certification gives you the quantitative surface quality data needed to qualify incoming materials, verify cleaning process effectiveness, and monitor contamination trends across your wafer lifecycle.
Particle Inspection Services
Laser Surface Scanning (SP2/SP3/SP5)
KLA-Tencor Surfscan SP series unpatterned wafer inspection systems provide the industry-standard platform for particle and defect detection on bare and blanket-film wafers. The SP5 (current generation) achieves <strong>sensitivity down to 0.09μm polystyrene latex (PSL) equivalent</strong> on bare silicon with full-wafer scanning in under 60 seconds per 300mm wafer. Earlier SP2 and SP3 models provide 0.16μm and 0.12μm sensitivity respectively. The dark-field laser scattering principle detects particles by their scattered light signature while discriminating against surface roughness (haze) and subsurface defects.
Particle Size Distribution Analysis
Beyond total particle count, particle size distribution (PSD) analysis provides critical insight into contamination sources and process cleanliness. A wafer with 50 adds of 0.2μm particles may be acceptable, while 5 adds of 2.0μm particles may not — PSD separates these cases. Our PSD analysis reports particle counts binned by size: 0.2–0.5μm, 0.5–1.0μm, 1.0–2.0μm, 2.0–5.0μm, and > 5.0μm, with per-wafer and per-lot histograms.
Full Wafer Defect Maps
Every particle detection event is recorded with its x,y coordinate, enabling generation of <strong>full-wafer defect maps</strong> showing the spatial distribution of particles across the wafer surface. These maps are essential for contamination source identification: a radial pattern suggests spin-coater or spinner contamination; random distribution suggests airborne or cassette-originated contamination; edge-concentrated particles indicate edge chipping or handling damage; localized clusters may indicate point-source contamination from a specific process step.
Haze Measurement
Haze is the <strong>non-localized background scattering signal</strong> measured by the laser surface scanner, representing sub-resolution surface roughness, very small particles below the detection threshold, or thin surface contamination layers. Elevated haze indicates poor surface quality — from incomplete CMP clean, residual slurry, chemical residue, or microscopic pitting — even when individual particle counts appear acceptable. Haze is reported in parts per million (ppm) of the incident laser intensity and is trended alongside particle count for comprehensive surface quality monitoring.
Pre-and-Post Process Delta Analysis
The most actionable quality metric is not the absolute particle count, but the <strong>particle adders</strong> — the difference between post-process and pre-process particle counts. A pre-process baseline scan establishes the initial particle count. After your process (or our cleaning/polishing service), a second scan quantifies particles added. The delta (adders) directly measures process cleanliness. For our internal processes, standard acceptance criteria are ≤ 10 adders at 0.2μm and ≤ 5 adders at 0.5μm for the full process sequence.
Process Flow — Particle Count Certification
來料檢驗與狀態確認
在 Class 1 潔淨室環境中進行晶圓接收。目視檢查是否有明顯污染、搬運損傷或可見缺陷。使用雷射劃線進行 ID 驗證。於 LIMS 登錄包含唯一的批次與晶圓 ID，以確保完整量測追溯性。採用載匣到載匣的搬運方式——不與晶圓進行人工直接接觸。
預掃描（基準測量）
初始雷射表面掃描建立來料粒子基準。以指定的靈敏度閾值（0.09–0.16μm，取決於 SP 型號與晶圓表面類型）進行全晶圓掃描。記錄粒子計數、尺寸分佈與缺陷地圖。此掃描作為後續若進行清洗/拋光時，添加劑計算的參考基準。
缺陷分類
自動缺陷分類（ADC）將顆粒與其他缺陷類型分開：劃痕（線性特徵）、滑移線（晶體學缺陷）、凹坑（表面空隙）以及堆垛層錯（晶體缺陷）。分類基於散射光強度、偏振以及空間特徵。對分類結果中存在歧義的缺陷圖像進行人工覆核。
霧度分析
量化整片晶圓表面之霧度。計算平均霧度值與霧度均勻性（以標準差佔平均值之百分比表示）。生成霧度地圖。並進行霧度與顆粒數之相關性分析，以辨識可能的根因（例如：霧度偏高而顆粒數偏低，可能指向CMP殘留而非顆粒污染）。
統計數據彙編
彙整所有顆粒數據，形成每片晶圓與每批次的統計彙總。於適用情況下，計算顆粒加成（以預掃描/後續掃描之比較為基礎）。針對晶圓來源進行SPC趨勢分析，對照歷史數據。當批次超出管制界限（通常為平均值 + 3σ）時，啟動失控處置計畫。
報告與認證
產出顆粒計數證書，包含：晶圓ID、掃描參數（量測儀器、靈敏度、掃描面積）、各尺寸bin之總顆粒數、顆粒加成（如適用）、缺陷地圖、霧度數據，以及依照客戶規格進行的通過/不通過判定。晶圓以配有乾燥劑的Class 1可兼容潔淨室盒匣進行真空密封保存。
Quality Specifications — Inspection System
| Parameter | Target Specification | Measurement Method |
|---|---|---|
| Minimum Detectable Particle | ≥ 0.09μm PSL (SP5) | PSL deposition standard wafer |
| Particle Count Accuracy | ± 10% (k=2) for ≥ 0.2μm | NIST-traceable PSL deposition standards |
| Scan Coverage | Full wafer minus edge exclusion | Edge exclusion: 3mm default, configurable |
| False Count Rate | < 1 false count per scan | Clean reference wafer, 10 scans |
| Haze Measurement Range | 0.05–500 ppm | Calibrated haze standards |
| Coordinate Accuracy | ± 50μm in X and Y | Laser-interferometer stage calibration |
| Throughput (300mm) | ≤ 60 seconds per wafer (SP5) | Cycle time measurement |
| Cleanroom Class | ISO Class 1 (ISO 14644-1) | Continuous particle monitoring |
All specifications based on KLA-Tencor SP5 system performance on bare silicon (100) wafers. Specifications for other surfaces (oxide, nitride, metal films, SOI) may differ due to increased background scattering. Contact us for film-specific capabilities. System calibration verified daily with NIST-traceable PSL deposition standards.
Dark-Field Laser Scanning — How It Works
The KLA-Tencor Surfscan system operates on the principle of dark-field laser scattering. A focused laser beam (typically 488nm argon-ion or 355nm UV, depending on model) is scanned across the wafer surface in a spiral pattern (r-θ scan). When the laser spot encounters a particle, the particle scatters light in all directions. Detectors positioned at oblique angles (outside the specular reflection path — hence "dark field") collect this scattered light. The scattered intensity correlates with particle size (larger particles scatter more light). Sophisticated signal processing algorithms discriminate true particle scattering from background noise caused by surface roughness (haze), film grain, and sub-surface defects. The system records the x,y location and scattered light intensity for each detected event, enabling generation of wafer maps and size distribution histograms.
Defect Classification — Beyond Particle Counting
Not everything that scatters light is a particle. The Surfscan system includes Automatic Defect Classification (ADC) capabilities that distinguish between different defect types based on their scattering signatures:
Particles
Discrete scattering events with well-defined, approximately Gaussian intensity profiles. Particles can be spherical (atmospheric dust, dried slurry residue), irregular (silicon fragments from edge chipping), or aggregated. Particles are typically the primary target of certification. Post-cleaning particle counts below 10 adders at 0.2μm are considered excellent for most applications; sub-5 adders is achievable with optimized cleaning protocols.
Scratches & Other Defects
Scratches appear as linear features with extended scattering profiles — recognized by ADC through their elongated spatial signature. Crystal defects (slip lines, stacking faults) produce characteristic linear patterns aligned with crystallographic directions and are distinguished from scratches by their straight, crystallographically oriented geometry. Pits (surface voids) appear as negative-contrast scattering events. Residue/stains produce diffuse scattering with low peak intensity. All defect types are reported alongside particle data to provide a complete surface quality assessment.
Particle Size Distribution & SPC Trending
The particle size distribution (PSD) provides significantly more diagnostic value than a single total particle count number. Consider two wafers, each with 50 total particle adds at 0.2μm. Wafer A shows 48 particles in the 0.2–0.5μm bin and 2 particles in the 0.5–1.0μm bin. Wafer B shows 35 particles in the 0.2–0.5μm bin, 12 in the 0.5–1.0μm bin, and 3 in the > 1.0μm bin. Wafer B represents a more severe contamination problem because larger particles have a proportionally larger "kill ratio" for device defects. PSD analysis enables process engineers to set size-bin-specific limits (e.g., ≤ 50 adds at 0.2μm, ≤ 10 adds at 0.5μm, ≤ 2 adds at 1.0μm) that more accurately reflect device-killing risk than a single total-count specification.
Edge Exclusion Zone Configuration
Particle count certification supports configurable edge exclusion zones — a radial band at the wafer perimeter where particles are excluded from the count because they fall outside the usable die area. Standard edge exclusion is 3mm for 200mm and 300mm wafers, but can be set to 1mm, 2mm, 5mm, or any customer-specified value. This is critical because particle counts in the extreme edge region (< 3mm from edge) are often 3–10× higher than in the central region due to edge handling and contact with cassette slots — and these edge particles may or may not be relevant depending on whether the customer uses that edge region for device fabrication.
SEMI M52/M53 Compliance
Our particle count certification reports are compliant with SEMI M52 (Guide for Specifying Scanning Surface Inspection Systems for Unpatterned Wafers) and SEMI M53 (Practice for Calibrating Scanning Surface Inspection Systems Using Deposited Polystyrene Latex Spheres on Unpatterned Semiconductor Wafers). This ensures that our particle count data is directly comparable with data from your in-house Surfscan systems and with your wafer supplier's particle certification — eliminating the "our scanner vs. your scanner" calibration discrepancies that can lead to false accept/reject decisions.
Class 1 Cleanroom Handling
All particle count certification is performed in an ISO Class 1 (ISO 14644-1) cleanroom environment — the most stringent level of cleanroom classification. In a Class 1 environment, the maximum allowable particle concentration is 10 particles per cubic meter at ≥ 0.1μm and 2 particles per cubic meter at ≥ 0.2μm. This ensures that the particles we measure originated from your wafer or process, not from our inspection environment. Cassette-to-cassette automated handling eliminates human contact with wafers. Wafer cassettes are stored in sealed containers with continuous dry N₂ purge when not actively being processed. All personnel wear full Class 1-compatible cleanroom garments (bunny suit, hood, booties, face mask, double gloves) and follow strict cleanroom protocols.