Wafer Dicing

Backgrind · tape mount · blade, laser, stealth and plasma separation

A 300 mm wafer leaves the fab about 775 µm thick. A DRAM die in a 16-high HBM4 stack has to come out under 46 µm, and one Japanese company, Disco, supplies most of the grinders, saws and blades that thin and cut it.

Wafer thickness from fab to package, in micrometers: a 300 mm wafer leaves the fab about 775 thick; standard wire-bond and flip-chip packages use dies 150 to 200 thick; mobile parts 75 to 100; a DRAM die in a 16-high HBM4 stack must average under 46 including its bond layer, because 17 dies must fit the 775 micrometer JEDEC height limit. Disco of Japan supplies most of the grinders, saws and blades that do the thinning and cutting. DIE THICKNESS, MICROMETERS (µm) Wafer out of the fab 300 MM WAFER 775 Standard package QFN, BGA, FCBGA 150 to 200 Mobile and wearable THIN FLIP-CHIP, WLCSP 75 to 100 HBM4 DRAM die 16-HIGH STACK <46 ONE HBM4 STACK: 16 DRAM DIES ON A BASE DIE 775 µm JEDEC limit 775 / 17 DIES = 45.6 µm EACH, BOND LAYER INCLUDED (COMPUTED) THINNING AND CUTTING TOOLS: Disco, Japan, supplies most
Wafer out of the fab
~775 µm
Standard die
150 to 200 µm
HBM4 DRAM die
<46 µm
Laser cutting, Disco
~70%
Methods
Blade, laser, stealth, plasma
Hub
Process

Dicing sequence

Backgrind, Mount, Cut, Clean

Dicing turns one sorted wafer into hundreds to tens of thousands of separate dies, each still on tape and ready for die attach.

The dicing sequence in four panels. Backgrind: the wafer is turned face down on protective tape and a grinding wheel removes silicon from the back. Tape mount: the thinned wafer is laminated to dicing tape stretched on a metal frame. Separation: a blade, laser or plasma cuts along the scribe streets. Clean and inspect: the dies sit separated on the tape, ready to be picked by the die bonder. 01 Backgrind THIN FROM THE BACK 02 Tape mount WAFER ON A FRAME 03 Separation CUT THE STREETS 04 Clean, inspect DIES READY TO PICK WHEEL REMOVED DEVICES FACE DOWN ONBACKGRIND TAPE FRAME AND DICING TAPE;WAFER NOW 50 TO 200 µm BLADE, LASEROR PLASMA KERF FOLLOWS THESCRIBE STREETS TO DIE ATTACH TAPE STRETCHED, DIESSPACED, OPTICAL CHECK DEVICE LAYER IN BLUE, TAPES IN VIOLET, FRAME IN COPPER. NOT TO SCALE.
Dicing sub-steps
Sub-stepWhat happensMain yield risks
BackgrindA grinding wheel removes silicon from the back of the wafer while backgrind tape protects the device sideSubsurface cracks, breakage, uneven thickness
Tape mountThe thinned wafer is laminated to dicing tape stretched across a metal frameAir bubbles, misalignment, tape letting go during the cut
SeparationA blade, laser or plasma etch cuts along the scribe streets between diesEdge chipping, microcracks, heat damage, off-street cuts
Clean and inspectRinse off debris, then optical inspection of every die on the tapeParticles, missed cracks

The wafer arrives from wafer sort with a map of good and bad dies. After dicing the dies stay on the tape until the die bonder picks the good ones. A die damaged here is a finished, tested die thrown away, which is why OSATs keep this room cleaner than the rest of the assembly floor.

Thinning

HBM Pushes Dies Below 50 µm

Target die thickness by package
PackageFinal thicknessHow it is reached
Standard wire-bond and flip-chip150 to 200 µmCoarse grind, fine grind
Mobile, wearable, WLCSP75 to 100 µm; 50 µm for the thinnestGrind plus polish or dry polish to remove damage
Stacked NAND and DRAMBelow 50 µmDicing before grinding (DBG) or stealth dicing before grinding (SDBG)
HBM4 DRAM core diesUnder 46 µm on average, bond layer included (computed)Carrier wafer and temporary bonding; grind to reveal the TSVs

A 300 mm wafer leaves the fab about 775 µm thick, four to 15 times thicker than the die that ships. Grinding leaves a layer of microcracks a few micrometers deep; if the wafer is ground thinner than that layer allows, its strength falls and breakage climbs. Lines therefore run a coarse grind, a fine grind and a final polish to remove the damage.

HBM sets the hardest target. JEDEC has raised the HBM4 package height limit from 720 µm to about 775 µm (reported July 2026), after memory makers said 720 µm needed DRAM thinner than current grinding can reliably make. A 16-high stack plus its base die puts 17 dies in that height, or about 45.6 µm per die with its bond layer. Wafers that thin cannot be handled alone, so they are bonded to a temporary carrier wafer before grinding and released after. The stacking side is covered on HBM.

Separation methods

Four Ways to Cut, Chosen by Thickness and Material

Four separation methods in cross-section. Blade: a diamond blade cuts a kerf tens of micrometers wide with some edge chipping. Laser ablation: a laser groove burns through the top layers, leaving a heat-affected zone. Stealth dicing: a laser focused inside the silicon writes a modified layer, and the tape is stretched to crack the wafer along it, with no kerf. Plasma: a mask leaves the streets open and a deep reactive ion etch cuts every street at once. Blade saw KERF TENS OF µm WIDE Laser ablation GROOVE, HEAT ZONE Stealth laser INTERNAL LAYER, NO KERF Plasma ALL STREETS AT ONCE MASK OPEN ON STREETS SILICON IN GRAY, DICING TAPE IN VIOLET, LASER IN PINK, MASK IN COPPER. NOT TO SCALE.
Separation methods
MethodHow it cutsBest fitLimits
Blade sawDiamond blade spinning at tens of thousands of rpm, cooled with waterStandard silicon at volume; the default on most linesChipping on thin wafers; kerf of tens of µm uses wafer area; struggles with brittle SiC and GaAs
Laser ablation and groovingPulsed laser burns a groove; often grooves low-k layers before a blade finishes the cutLow-k dielectric stacks, thin wafers, narrow streetsHeat-affected zone and debris; slower than a saw on thick wafers
Stealth dicingLaser focused inside the silicon writes a weakened layer; stretching the tape cracks the wafer along itMEMS, image sensors, memory, any debris-sensitive dieNeeds clear streets with no metal test pads; licensed technology (Hamamatsu engines in Disco tools)
Plasma dicingMask the dies, then deep reactive ion etch cuts every street at onceVery small dies, very thin wafers, die strengthNeeds a mask step; metal and test structures in the street must be cleared

Most lines run blade saws as the workhorse and qualify a laser or plasma method for the products that need it. Laser grooving followed by a blade is now standard for logic wafers with fragile low-k dielectric in the interconnect stack.

Streets and yield

Narrow Streets Pay Off Only for Small Dies

Dies per 300 mm wafer: 80 µm street against 20 µm street
Die size (square)80 µm street20 µm streetExtra dies
0.5 mm208,975260,131+24.5%
1 mm59,98567,288+12.2%
2 mm16,01816,993+6.1%
5 mm2,6082,672+2.5%
10 mm630638+1.3%

Computed with the standard gross-dies-per-wafer formula, before edge exclusion and yield. Street widths are illustrative: blade-cut streets commonly run 60 to 100 µm, and plasma and stealth dicing allow far narrower ones. The gain matters for small discretes, RFID chips, sensors and power devices, and barely registers for a large processor die. Plasma dicing also cuts all streets in one etch, so its time per wafer does not rise with die count, while a saw's does.

Lines track four numbers at this step: die yield after dicing, chipping rate, street width and wafers per hour.

Tools and consumables

Disco Makes the Tools and the Blades

Dicing tools and consumables
CategorySuppliersNotes
Grinders and polishersDisco, Accretech (Tokyo Seimitsu), OkamotoDisco also sells the grinding wheels
Blade dicing sawsDisco, AccretechDisco also makes most of the blades its saws use
Laser dicing and groovingDisco, Accretech, EO Technics, ASMPT, Synova; Hamamatsu stealth laser enginesDisco holds about 70% of laser cutting (JW Insights)
Plasma dicingPlasma-Therm (St. Petersburg, Florida), SPTS (KLA), PanasonicPlasma-Therm is the US toolmaker at this step
Backgrind and dicing tapesLintec, Nitto Denko, Furukawa Electric, Mitsui ChemicalsUV-release tapes let the bonder lift dies cleanly
Die-attach film laminated before dicingResonac, Nitto Denko, LintecSee Die Attach

Disco does not publish a market share, but no other company sells a full line of grinders, saws, laser dicers and the wheels and blades they consume. It runs near full capacity on AI demand: it reported sales up 27% and profit up 44% for April to June 2026, its first fiscal quarter. Thinning and dicing HBM, CoWoS and hybrid-bonded wafers all run through its tools.

China

China Starts With Laser Dicing

China still imports most of its wafer saws and grinders, mainly from Disco and Accretech. Domestic makers are moving in through lasers first: Shenzhen Tensun Precision built China's first 300 mm laser dicer in 2016, and Suzhou Lumi Laser makes laser grooving tools used on 300 mm wafers below 28nm and stealth dicing tools for MEMS and memory. Chinese OSATs such as JCET, Tongfu and HT-Tech run mostly Disco and Accretech lines.

Record

Page Record

This page also carries the material from the former Dicing and Die Prep page.

Covers
Backgrind, tape mount, separation methods, street width and dies per wafer, tools and consumables, and China's position
Sources
Digital Today (JEDEC HBM4 height limit, July 2026); MarketScreener (Disco quarterly results, July 2026); JW Insights (Disco laser cutting share; Tensun and Lumi Laser); Disco, Hamamatsu and Plasma-Therm product pages; dies-per-wafer and HBM per-die figures computed
Last verified
October 2026