On any chip recycling inspection bench, 90% of grading decisions are made at the "visual" stage. XRF, bad-block testing, and functional read-outs are the "confirmation" step — laser marking is the "pre-judgment." A single BGA NAND chip, examined for 3 seconds under a 10× magnifier, tells you whether it is most likely an original die, a white chip, or a black chip, and whether it shipped in 2026 or sat in inventory since 2023.
NAND Flash chip recycling starts with package form: BGA (Ball Grid Array) chips come mostly from SSDs and USB drives; TSOP (Thin Small Outline Package) chips are common in older memory cards and budget USB sticks; then there are wafers and singulated dies. After sorting by package, the next step is reading the laser marking — a clear etch with complete part number + date code + brand logo points to an original die; a faded, partially missing, or re-polished marking points to a white chip (failed full wafer test) or even a black chip. No instruments needed: a 10× magnifier and a 40× stereomicroscope are sufficient.
The date code (Cycle Code) is the chip's "birth certificate." The mainstream format is YYWW (last two digits of year + week number):
Placement varies by brand: Samsung places it below the part number (typically 7-8 digits); SK Hynix puts it in the top-right corner (6 digits); Kioxia (formerly Toshiba) embeds it within the part number string; Micron marks the back or side of the die; SanDisk/WD follows the Kioxia convention.
Date code directly affects pricing: for the same part number and capacity, a 2026 fresh die commands a 5%-10% premium over a 2023 inventory chip — simply because the newer die has a lower bad-block rate, which downstream SSD and module manufacturers prefer.
| Marking State | Microscope Features | Verdict | Pricing Impact |
|---|---|---|---|
| Tier A (Sharp) | Crisp etch; complete PN + date code + logo; no polishing marks | Original die | Base price |
| Tier B (Faded) | Blurred characters; partial digits missing; light grinding trace | White chip suspect | 70-80% of base |
| Tier C (Missing/Re-etched) | No marking; or clearly added later; uneven depth; chipped edges | Black chip / refurbished | Scrap or 50% of base |
Practical tip: under a 40× stereomicroscope, check etch depth. Original laser etching is uniform (≈5-10 μm); re-etched dies show inconsistent depth and chipped edges. UV light can reveal fluorescent residue from chemical-etch refurbishment.
| Category | Spec | Reference Price (CNY) | Notes |
|---|---|---|---|
| NAND BGA | 64GB TLC | 8-15 / chip | Volume mainstream |
| NAND BGA | 128GB MLC | 20-35 / chip | MLC premium 30-50% |
| eMMC | 64GB Consumer (pulled) | 35-50 / chip | Phone repair demand floor |
| eMMC | 64GB Industrial (-40~85°C) | 60-80 / chip | Stable industrial/automotive demand |
| eMMC | 128GB MLC (Samsung/Kioxia) | 20-35 / chip | Longer P/E cycle life |
Notes: Chips with bad-block rate above 5% are discounted to 60-80% of the listed price. Industrial-grade inventory with original factory test reports (-40°C to 85°C) carries a 20%+ premium. Prices are driven by the NAND Flash market cycle and OEM production cuts, with a 6-12 month volatility window.
Mixed lots: if a box contains BGA and TSOP together, or NAND mixed with eMMC, sort by package first, then by marking, then by capacity and wafer grade. Unsorted mixed lots are priced at the lowest tier — a 64GB TLC mixed lot may fetch only 8 CNY, while a properly sorted lot reaches 15 CNY.
MemoryRecycle (Contact: Mr. Wu, Tel: 188-2424-1693) is a year-round buyer of NAND/eMMC chips and server memory modules, accepting all package forms (BGA/TSOP/Wafer/Die). Our inspection bench is equipped with 40× stereomicroscopes and XRF analyzers, with same-day graded quotes on incoming lots.