1

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PageIntroduction 3WINTER diamond ID saw development 4The diamond ID saw blade 5Saw blade dimensions and basic dataLayer specification 6

BondConcentrationGrit

ID saw blade program 7Core material 8Development and innovation 8

L-type and LB-typeCuttting width improvements 9

Application of diamond ID saw blades 10Tensioning of ID blade

Using central ring tensioning system 11Using mechanical tensioning system 12

Measurement of ID saw blade stability 13Measurement of blade deflection 13Measurement of ID elongation 14Cooling 14Silicon slicing parameters 15Crystal mounting 15Slice tolerance 16Blade start up 18Problem elimination 18Slice tracking system 19Safety precautions 19Other materials 20Dressing and sharpening ID saws 20Questionnaire 24

Contents

3

Introduction

The ID saw blade consists ofa thin circular steel core,which is tensioned at itsoutside diameter (OD) andhas its diamond cuttingedge electrodeposited onthe inside diameter (ID).In comparison withconventional saw blades,which are mounted at thecenter and have their cuttingedge at the OD, the ID sawblade is capable of cuttingthe same materials withconsiderable reduction insawing loss (kerf).In addition, the stability andhigh tension of the ID sawblade core enable it to cutthinner slices than possiblewith conventional sawblades.

ID saw blades were initiallyused for slicing germaniumand silicon semiconductormaterials. These materialsstill account for the majorusage of ID blades, butrecently there has been anincrease in the slicing ofmaterials such as GGG,samarium cobalt, sapphireand quartz.

WINTER has been making IDsaw blades since 1958. Theearly blades had an OD of 81/8 inch and were capable ofslicing the small diametergermanium and siliconmaterials available at thattime. Over the past two

decades blade technologyhas been continuouslyupdated to keep pace withthe ever increasing tempo ofsilicon crystal development.In 1979, WINTER became thefirst blade manufacturer tosell 27 inch diameter IDblades to the electronicsindustry, permitting theslicing of crystals up to 6inches in diameter.

At the Productronica tradefair in Munich in 1983,WINTER achieved a world„first“ at that time new 34"ID saw blade. Developmentof these blades hasprogressed so that they areused for slicing 8" siliconwafers.

WINTER will continue towork together closer withthe key end-users andoriginal equipmentmanufacturers on furtherdevelopments of ID sawingtechnology.

Considerable experience isrequired in the selection andproper usage of ID sawblades. The presentcatalogue contains helpfulinformation but does notclaim to answer all questionswhich arise. For furtherinformation please contactthe WINTER company oryour localWINTER sales representative.

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The production of blades isdependent on proper qualitycontrol of the steel core,diamond quality and gritsize, and electroplatingbaths, and on strictadherence to the controlledprocess parameters. Acomputer assisted processchecking system isconducted in order to ensureuniform quality.

WINTER diamond ID saw blade development

Publications.Publications.Publications.Publications.Publications.Cutting Sapphire with AnnularSaw Blades, Industrial DiamondReview, 37 (1977), No. 2

Trennen von Samarium-KobaltmitDiamant-Innenlochsägeblättern(Cutting of Samarium Cobalt withID Saw Blades), Industrie Diaman-ten Rundschau 12 (1978) No. 3

Diamantwerkzeuge für dieElektronikindustrie (DiamondTools for the Electronics Industry),Feinwerktechnik und Meßtechnik

1985, No. 3Schärfen von Innenlochsägen -Untersuchung des Einflusses derstofflichen Parameter vonSchärfsteinen auf die Diamantenund die Bindung an der Innen-lochsäge (Sharpening ID SawBlades - investigation of theinfluence of material parametersof dressing sticks on diamondsand bond of the ID saw blade)Diploma thesis by MichaelKleinert, 1988

WINTER has a well equippedresearch and developmentlaboratory available forinvestigation of theelectroplating process andplating material. Thisdevelopment set-up is usedto test various types ofdiamond and bonds and todetermine the type bestsuited for ID saw blades.

The WINTER TechnologyCenter, worldwideresponsible for applicationdevelopments, possessesamong other an ID sawingmachine equipped withinstrumentation formeasuring cutting force,deflection, and instrumentfor deflection adjustment bypneumatic; this permitsinvestigation of machineparameters for the slicing ofdifferent materials and alsoinvestigation of coolants.

(In 1976 WINTER developed arotating ingot fixture thatmade slicing of sapphirepossible). Another importantachievement was thedevelopment of a samariumcobalt slicing process,involving the optimization ofslicing parameters and theintroduction of a specialcoolant). This method hasbeen improved several timesin recent years.

The work of the WINTERresearch & developmentlaboratory has produceddetailed knowledge of thesharpening / dressingprocess for ID saw blades.The resultingrecommendations fordressing/ sharpening aregiven in the section on“Dressing and sharpening IDsaws”, starting on page 20.

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1 Saw Blade Dimensionsand Basic DataStructure of ID sawbladeThe ID saw blade ischaracterised by a thin, ring-shaped core, the innerdiameter of which isdesigned as a cutting edge.

CoreThe steel core is made ofhigh strength, cold rolled,stainless steel.The core thickness has amajor effect on the stabilityof the sawblade and thus ontool life and the quality ofthe sliced wafers.The core thickness cannot beincreased at all withoutchanging the cutting layergeometry. This means thereis a trade-off between kerfloss and tool stability.

GritNatural diamond with gritsize D46 is recommended forthe silicon slicing operation.The grits available are D46X71, D46B X58, and D46CX50.

Nickel bond

Alternatively it is possible tochoose between two bondvariants which are differentin hardness.Bond G820 (standard bond)is softer than G825.

The diamond ID saw blade

Cutting edge geometry

Type S35D

X1 = 2.0 mm *)

*) Ø 34“ : X1 = 3.0 / 4.0 mm

T

E

X = 0,10 mm

Winter universal design.Cutting edge without without without without without mechanical treatment

Type S35B & SL35B

X1 = 2.0 mm *)

*) Ø 34“ : X1 = 3.0 / 4.0 mm

T

E

X

Winter universal design.Cutting edge thickness with mechanical treatment

ChamferChamferChamferChamferChamfer C

Type S35E

X1 = 4.0 mm *)

*) also 2.2 mm

T

E

X = 0.40 mm

Winter rugged universal design.The plating envelops a greater part of the blade core

Figure 1

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2 Layer specificationAlongside variations ofgeometry, cutting width andcore thickness variation, thefollowing possibilities areavailable for adjustment ofID sawblades to meetcustomer specifications.

- Bond variation- Concentration variation- Grit variation

2.1 BondNickel bonds aredistinguished by hardness.Measurement of bondhardness is effected in thebond structure, which ispermeated with the grit. Inunfavourable cases thatmeans there is grit directlybehind the measuringpoints, so measurementincludes not only the nickelitselve. Thus it is importantnot to neglect the influenceof the grit.

Standard:G820: This bond is used themost frequently, and is thestandard bond for IDsawblades. It retains the gritoptimally in the bond.

Hard bond:G825: This bond ischaracterised mainly by highwear resistance. It is used inprocesses where frequentdressing is required forquality reasons.

2.2 Concentration2.2 Concentration2.2 Concentration2.2 Concentration2.2 ConcentrationConcentrationConcentrationConcentrationConcentrationConcentrationspecificationspecificationspecificationspecificationspecificationThe grit concentration,measured in grit particlequantities per gram of nickeldeposition, can be variedwithin a permissiblespectrum. The maindistinction is betweenstandard concentration andhigh concentration.Influence of concentrationInfluence of concentrationInfluence of concentrationInfluence of concentrationInfluence of concentrationChanges in concentrationbasically have the followingeffect on processparameters.

2.3 Grit2.3 Grit2.3 Grit2.3 Grit2.3 GritStandard gritStandard gritStandard gritStandard gritStandard gritNatural grit D46 in varioussizes has becomeestablished for practicaloperation in silicon slicing:The finer the grit, the betterthe surface quality of thewafer, but the smaller theavailable amount of chipspace.

The WINTER standard ofnatural diamond is based onthe FEPA standard formicron powder sizes.The main difference is thatWINTER uses closerfractioning.For special applications (rodcropping) bigger grit sizes(up to D181) are available.

Concentrationstandard high

Grit spacing medium lowGrit simultaneously in contact medium highNormal force medium highLoad per grit medium lowBearing proportion high lowWafer surface good very goodChip space medium low

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ID saw blade program

LegendDDDDD::::: Outer diameterDDDDD11111::::: Inner diameterT:T:T:T:T: Cutting widthX:X:X:X:X: Layer heightE:E:E:E:E: Core thicknessXXXXX11111::::: Length of layer

Type Ø D Ø D1 T X E X11111mm inch mm inch mm mm mm mm206 8

1/8 83 3

1/4 0.26 0.15 0.1 2.0

257 10 1/8 101 4 0.26 0.15 0.1 2.0

304 12 115 4 1/2 0.26 0.15 0.1 2.0

422 16 5/8 153 6 0.26-0.29 0.10 0.10 2.0

546 21 1/2 184 7

1/4 0.27-0.32 0.10 0.12 2.0

203 8 0.27-0.32 0.10 0.12 2.0

235 9 1/4 0.30-0.32 0.10 0.15 2.0

S35D 558 22 203 8 0.26-0.32 0.10 0.12-0.15 2.0

235 9 1/4 0.30 0.10 0.15 2.0

596 23 203 8 0.27 0.10 0.12 2.0

690 27 1/6 203 8 0.35 0.12 0.15 2.0

235 9 1/4 0.26-0.29 0.10 0.10-0.13 2.0

0.29-0.35 0.10 0.15-0.17 2.0

240 9 1/2 0.28-0.31 0.10 0.13-0.15 2.0

0.31-0.34 0.10 0.15 2.0-3.0

860 34 304 12 0.27-0.33 0.10 0.15 3.0-4.0

0.32-0.39 0.10-0.12 0.17 3.0

206 8 1/8 83 3

1/4 0.29 0.1 0.1 2.0

257 10 1/8 101 4 0.29 0.1 0.1 2.0

304 12 115 4 1/2 0.29 0.1 0.1 2.0

422 16 5/8 153 6 0.26-0.29 0.12-0.15 0.10 2.0

S35B 546 21 1/2 184 7

1/4 0.29-0.31 0.15 0.12 2.0

558 22 203 8 0.27-0.31 0.15 0.12 2.0

596 23 203 8 0.29 0.15 0.12 2.0

690 27 1/6 235 9

1/4 0.28-0.31 0.15 0.13-0.15 2.0

240 9 1/2 0.29-0.30 0.15 0.13 2.0

860 34 304 12 0.38 0.15 0.17 4.0

546 21 1/2 184 7

1/4 0.30 0.13 0.12 2.0

SL35B 690 27 1/6 235 9

1/4 0.28-0.30 0.13 0.13-0.15 2.0

240 9 1/2 0.30 0.13 0.15 2.0

860 34 304 12 0.30 0.13 0.17 3.0

422 16 5/8 153 6 0.29-0.35 0.40 0.12 4.0

546 21 1/2 184 7

1/4 0.35 0.40 0.15 4.0

203 8 0.40 0.40 0.17 4.0

S35E 558 22 203 8 0.30 0.40 0.12 4.0

690 27 1/6 235 9

1/4 0.37 0.40 0.17 2.2/4.0

240 9 1/2 0.25 0.30 0.15 3.0

290 11 1/2 0.37 0.40 0.17 4.0

860 34 304 12 0.37-0.43 0.40 0.17-0.20 4.0

Table 1: Other dimensions available on request.

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4 Development andinnovation

4.1 L-type and LB-typeContinous furtherdevelopment work is inprogress, achieving inparticular longer blade life,combined with improved

wafer surface.The new development workis based on the provenD-type and B-type.Optimisation concepts arebeing realised and tested on

3 C3 C3 C3 C3 Cororororore mae mae mae mae materialterialterialterialterial

Main requirementsThe WINTER core materialhas to meet the highestquality requirements:- Isotropic material- Stainless steel- Special chemical

composition- Specific surface

quality and measuringsystem

- High yield strength- Defined elongation,

measured by a specialWINTER test

- Defined etchingbehaviour

Quality assurance during production

- Defined corrosionbehaviour

- Low core thicknesstolerance

the basis of this teardropgeometry.

There is also a newlydeveloped process, thelinearisation process (L),

Figure 2: Quality assurance during production

Coil Square Core Blade

Steps of - Define - Stamp - Special WINTER - Ni-platingQA specification of - Mark with WE-No. technology for - Process control

delivery In roll direction core production - Saw inspection- Define test - Visual inspection - Drilling - Customer

procedures (colour change, - Inspection on certificates- Perform incoming grooves, dents, special fixtures

inspection etc.) (centering bores)

Sketch

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giving the following benefitscompared with conventionalmanufacture:

- More consistant builtupof layer structure

- Restriction of cuttingwidth variation withinone ID sawblade

This method is used in orderto offer a linearised B-type)which is analogous to the B-type (WINTER designation:LB-type). If necessary, theblades may have to beadapted to the customer’sprocess parameters.

With a linearised sawblade,the cutting width is moreuniform, which means thatthere is much less cuttingwidth difference within asawblade.Due to the reduction inmaterial losses resultingfrom axial runout andvibration, the dimensions ofthe cutting slit are definedmore accurately.In order to ensure good,constant wafer qualitylinked with long blade life,the kerf loss is reduced,particularly in the startupphase of the blade. This isreflected in higher yield andhigher productivity.First conclusions can bedrawn on the applicability ofthis new type from practicaltests. The results led to thelatest development of theLB-type. This type was

developed specially for thin-kerf applications. It featuresno-problem startingbehaviour, and permitscontinuous operation. Dueto the production processthe LB-type has an X-dimension of 0.13mm (the D-type has an X-dimension ofonly 0.10mm), thus anincrease of lifetime ofapprox. 20% can beexpected.

4.2. Cutting widthimprovements

ToleranceA narrowing of toleranceshas become possible thanksto ongoing technicalprogress. Further researchwill show more developmentpotentials.

Figure 4: Tolerances

Fig. 3: Comparison of cutting width deviation for different ID types

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Improper blade mountingcan lead to the followingproduction problems:

a) High slice rejection rateb) Poor product qualityc) Strain on operating

personneld) Reduction in cutting

speede) Poor blade stabilityf) Short blade life.

Thus it is evident thateconomical and optimumuse of the ID saw can only beachieved through properblade mounting andtensioning. There are twoblade tensioning systemscurrently in use in theindustry: “mechanicaltensioning”, and “centralring tensioning” (Fig. 5).These systems will achieve

Figure 5:a = Clamping ring, b = Clamping screw, c = Tensioning ring,d = Tensioning screw.

Central ringtensioning

Mechanicaltensioningclampingrings

Handling of ID saw blades

ID saw blades are highlysusceptible to damage dueto the thinness of theircores, and are hard to handlein the untensioned state dueto their low rigidity.WINTER recommends that IDblades be kept in their origi-nal package until usage.Great care should be takento avoid kinking bladeswhen handling them. In theevent of damage to a blade,WINTER advises that theblade should be scrapped.Gloves should be worn whenhandling blades in order toavoid injuries such as cuts,etc.

The sawing machine

Rigid and vibration-freeconstruction of the ID saw isessential. There must beprovision for the sawingslurry to escape, sinceotherwise the accumulationof slurry in the blademounting head may lead tovibration. To assureelimination of all slurry fromthe head, it is recommendedto install a back flash nozzlewhich applies coolant inorder to keep the core clean.In addition, the ID sawingmachine should fulfill the

following requirements:

a) Stepless cutting speedregulation of ingot crossfeed into the bladecutting edge

b) Stepless speed controlfor achieving theoptimum bladerotational speed neededfor cutting differentmaterials

c) Indication and control ofcoolant flow

d) Automatic slice removale) Slice tracking systemf) System for automatic

correction of deflection.

Mounting of the ID sawblade

Expert mounting andtensioning are essential forthe proper functioning ofthe ID blade.

Application of diamond ID saw blades

a

d

c

ba

c

d

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Tensioning of ID blade using central ring tensioningTensioning of ID blade using central ring tensioningTensioning of ID blade using central ring tensioningTensioning of ID blade using central ring tensioningTensioning of ID blade using central ring tensioningsystemsystemsystemsystemsystem

1: Remove clamping ring bleedscrew and metal tensioning ring.Reinsert bleed screw and tightenit. Clean and degrease clampingring surface.

3: Clean metal tensioning ring,cover the tensioning area with alight coat of lubricant and insertring in the clamping ring groove.

4: Clean and degrease clampingareas. Clean blade tensioningsupport area and cover the areawith a thin coat of lubricant.

2: Clean and degrease the bladeclamping areas (on each side) andposition the blade on the clampingring guide pins.

good results provided thatblade set-up is of professio-nal quality.

In addition, special attentionshould be paid to thefollowing steps:

a) Thorough cleaning anddegreasing of clampingring

b) Inspection of tensioningring for surface defectsand remedy if necessary

c) If the saw is fitted with asingle-slice removalsystem, this system mustbe inspected for propercondition of the pick-upface and for correctsetting.

5: Positioning of elongation meterin the ID of the blade.

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8: Clean and degrease upperclamping ring.

9: Match up balance marks ofclamping rings and place upperclamping ring properly aligned ontop of blade and lower clampingring.

10: Place screws into clampingrings and tighten screwshand-tight.

Tighten clamping screwscrosswise using an Allen wrench.Generally the clamping ringscrews (M6 property class 12.9) aretightened with a torque wrench to15 Nm. To avoid screw failure,screws should be replaced at everyblade change.

12: Clean tensioning ring and coverit with a thin coat of grease.

14: Set up a dial gage and centerblade ID by tightening 4 clampingscrews crosswise. Accuratecentering at this time is the basisfor the final blade set-up andcentering accuracy. Tension bladeand adjust blade run-out duringthis operation according toTable 2.

Obtain the proper elongationvalue from Table 2.

13: Mount clamping rings with sawblade on top of tensioning ring.

15: Measurebladedeflection asshown onpage 13. Ifbladedeflection isbelow thevalue givenin Table 2further

tensioning of the blade is needed.

Tensioning of ID bladeTensioning of ID bladeTensioning of ID bladeTensioning of ID bladeTensioning of ID bladeusing mechanicalusing mechanicalusing mechanicalusing mechanicalusing mechanicaltensioning systemtensioning systemtensioning systemtensioning systemtensioning system(clamping rings)(clamping rings)(clamping rings)(clamping rings)(clamping rings)

6: Clean and degrease lowerclamping ring.

7: Clean and degrease bladeclamping area. Place blade inclamping position on lowerclamping ring without touchingthe cleaned and degreasedclamping area.

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Measurement of ID sawMeasurement of ID sawMeasurement of ID sawMeasurement of ID sawMeasurement of ID sawblade stabilityblade stabilityblade stabilityblade stabilityblade stability

The ID saw blade receivesthe required stabilitythrough tensioning. Properblade tension and stabilityare the most importantfactors for good slice qualityand slice properties.The stability or rigidity of theblade is the resistance to aside thrust perpendicular tothe blade at or near the IDdiamond cutting edge.This ID blade stability andrigidity can be determinedusing the followingmethods:a) Measurement of

elongation (holeenlargement)Result: inaccurate

b) Measurement of run-outResult: very accurate

c) Measurement of bladedeflectionResult: very accurate

Measurement of bladeMeasurement of bladeMeasurement of bladeMeasurement of bladeMeasurement of bladedeflectiondeflectiondeflectiondeflectiondeflectionThe resistance of a blade to aforce acting perpendicularlyon it can be used as anindirect indicator for theinternal tensions of theblade. In practice, industryhas made this measurementwith a constant force andmeasures the deflection ofthe blade. This deflection ismainly dependent on theblade geometry and on IDelongation. For successful ID

slicing, the variousdeflection data should beattained as a function of thespecific ID saw, dependingon production process.

The following points mustbe defined:a) ID elongationb) Measuring pointc) Deflection forced) Handling.

a) ID elongationa) ID elongationa) ID elongationa) ID elongationa) ID elongationID elongation is the increasein blade ID that is caused bytensioning of the blade. Theincrease in ID is measured inmicron (inch).

b) Measuring pointsb) Measuring pointsb) Measuring pointsb) Measuring pointsb) Measuring pointsThe deflection of the IDblade is measured at threepoints, 120° apart. Thedistance between themeasuring point and the IDis 5 mm, (see Fig. 6).c)Deflection forcec)Deflection forcec)Deflection forcec)Deflection forcec)Deflection forceThe deflection measuring forinternal tensioning testsafter the production processis done with a test force of1.7 N ± 0.02 N. Depending on

the arrangement, this forcecan be applied either by aspring or by a weight, actingperpendicularly to the planeof the blade.

d) Handlingd) Handlingd) Handlingd) Handlingd) HandlingThe deflection of the blade ismeasured by means of agage, with a force appliedperpendicularly to the planeof the blade.

The tip of the gage is placedon the three measuringpoints, and then calibratedby means of thepretensioning force (0.3 N).

Then the additional testingforce (of 1.4 N) is applied bymeans of a weight or byspring force. The deflectionof the blade is read off onthe length measuring unit.

The differences between thethree readings may notexceed 2 µm. If there is agreat difference betweenthe readings, the tension inthe blade is not uniform.

Figure 6

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The radial run-out of the IDsaw blade has an influenceon vibration in the slicingprocess. The smaller theradial run-out, the lower thevibration level in the slicingprocess.

CoolingThe coolant generally usedfor silicon slicing is deonizedwater with a coolant additi-ve. The dilution range isdependent on manufacturerrecommendation.

The coolant additivesgenerally used are surfaceactive fluids and syntheticcoolant oils. A coolant additi-ve should always be usedunless process difficultiesare thereby caused, since theeffects on surface quality,yield, blade life and cuttingspeed are positive.

For other materials,synthetic coolants or cuttingoils may be of value. Furtherinformation on coolants isgiven in Table 5 on page 19.

The coolant nozzles shouldbe positioned as indicated inFig. 6. Coolant nozzlesshould be positioned in sucha way that the coolant flowis evenly split. An even splitof the coolant stream willensure even wear of theblade.

Studies show that theinfluence of cooling (modeof supply and flow rate) havea considerable influence onthe result of the slicingprocess and the life of the IDsaw blades.

Measurement of IDelongationID elongation is a result ofthe tensioning process. Aselongation is increased, thetension and also the rigidityof the blade increases. TheID elongation can give anindication about the rigidityof the ID blade; however,this is only an indirect clue,since changes in saw bladedesign affect the rigidity ofthe blade, and thus withequal ID elongation theblade will develop differentvalues for the restoringforce. If a fixed value of IDelongation is used for bladestability as a standardwithout deflectionmeasurement, a variation inthe performance of the sawblades must be tolerated.Loss of blade rigidity will beexperienced over the life ofthe blade.Retensioning towards theend of blade life is notnormally recommended.

At the same time as IDelongation, radial run-out isalso measured. The radialrun-out should be as smallas possible, and at any ratenot more than 0.0008 inch(0.02 mm).

Figure 7

15

Silicon slicing parameters

The blade manufacturershould confine himself topublishing averageperformance data which canbe obtained with proper useof the blades. The data in the

table below are given asguidance and comparisonfor the user.

Crystal mounting

Many different mountingmaterials are used e. g.

graphite, carbone fibre,ceramic, etc. The rightselection of the mountingbeam plays a major role insuccessful slicing, since theblade enters the mountingbeam after each cut throughthe crystal.

Type Ø DA Ø DI ID elongation Further Infeed Max. materialelongation diameter

mm inch mm inch mm µm mm/min mm206 8

11111/////88888 83 3

11111/////44444 0.4-0.5 50 30-60 32

257 10 11111/////88888 101 4 0.5-0.6 50 30-60 40

304 12 115 4 11111/////22222 0.7-.0.8 50 30-60 51

422 16 55555/////88888 153 6 1.1-1.2 50 30-70 76

546 21 11111/////22222 184 7

11111/////44444 1.4-1.5 50 30-70 127

203 8 1.5-2.0 50 30-70 127

235 9 11111/////44444 1.5-2.1 50 30-70 127

S35D 558 22 203 8 1.5-2.0 50 30-70 127

235 9 11111/////44444 1.5-2.1 50 30-70 127

596 23 203 8 1.5-2.0 50 30-70 127

690 27 11111/////66666 203 8 1.9-2.0 50 30-70 152

235 9 11111/////44444 1.9-2.1 50 30-70 152

240 9 11111/////22222 1.9-2.1 50 30-70 152

860 34 304 12 2.3-2.4 50 30-70 203

206 8 11111/////88888 83 3

11111/////44444 0.4-0.5 50 30-60 32

257 10 11111/////88888 101 4 0.5-0.6 50 30-60 40

304 12 115 4 11111/////22222 0.7-0.8 50 30-60 51

422 16 55555/////88888 153 6 1.1-1.2 50 30-70 76

S35B 546 21 11111/////22222 184 7

11111/////44444 1.4-1.5 50 30-70 127

558 22 203 8 1.5-2.0 50 30-70 127

596 23 203 8 1.5-2.0 50 30-70 127

690 27 11111/////66666 235 9

11111/////44444 1.9-2.1 50 30-70 152

240 9 11111/////22222 1.9-2.1 50 30-70 152

860 34 304 12 2.3-2.4 50 30-70 203

546 21 11111/////22222 184 7

11111/////44444 1.4-1.5 50 30-50 127

SL35B 690 27 11111/////66666 235 9

11111/////44444 1.9-2.1 50 30-50 127

240 9 11111/////22222 1.9-2.1 50 30-50 127

860 34 304 12 2.3-2.4 50 30-50 203

422 16 55555/////88888 153 6 0.9-1.0 50 30-70 76

546 21 11111/////22222 184 7

11111/////44444 1.1-1.2 50 30-70 127

203 8 1.3-1.6 50 30-70 127

558 22 203 8 1.3-1.6 50 30-70 127

S35E 690 27 11111/////66666 235 9

11111/////44444 1.5-1.9 50 30-70 152

240 9 11111/////22222 1.5-1.9 50 30-70 152

290 11 11111/////22222 1.7-2.0 50 30-70 152

860 34 304 12 2.0-2.2 50 30-70 203

Table 2: Other dimensions available on request.

16

The crystal is mounted withepoxy to the mountingbeam. Great care must betaken in the mounting of thecrystal to assure a strongbond between crystal, epoxyand mounting beam. Assoon as the epoxy ishardened, the excess epoxyis removed to avoid anygum-up of the cutting edge.Good results have beenobtained with A46 (Hahn &Kolb) and with ARALDITE(CIBA GEIGY).

Slice toleranceSlice toleranceSlice toleranceSlice toleranceSlice tolerance

Slicing conditions,performance and life of theID saw blade are markedlyinfluenced by the requiredslice tolerance.In most cases tighter slicetolerances necessitate anincrease in blade treatmentlike dressing and tensioning.Tolerances are generallyconnected with a certainmaterial diameter. Withincreased material diameter,slice tolerances need to be

looser.Figure 8 depicts thegeometrical features of aslice, that are covered by atolerance.Bow tolerance is critical,since this defect couldcontribute to waferbreakage under certainconditions during the slicingoperation.

Bow may be due to variouscauses:a) Non-uniform slice surface.Surface irregularities(damage) or saw marks arefound to be the cause of bow

in 90% of the slices that areaffected by bow. Eliminationof this defect can beaccomplished by etching(see Fig. 9a).b) Wandering of the bladeduring slicing.This defect is caused by lowblade tension and / or dullblade (see Fig. 9b).

A distinction is madebetween positive and nega-tive bow (see Figs. 9c and9d). The notation positive ornegative has been derivedfrom the positive or negativeslice contour.

Slice thickness Slice taper

Slice bow Slice chipped

a b

a-b

Figure 8

17

With the positive bow thewafer moves away from thecenter; for this reason nofriction is caused betweenwafer and crystal. In thiscase the slice cannot bepulled off, thrown or brokenby the blade (see Fig. 9c).With negative bow thewafer bends towards theblade. Friction forces can

develop between wafer andblade, and they can be ofgreater magnitude than theforce that holds the slice tothe epoxy. In this case thewafer will be pulled off theepoxy and broken.

(For elimination of thesedefects see Trouble ShootingGuide)

a) Bow caused by surfaceirregularity

b) Cut waferbendstowardsblade core

c) Positve bow

Cut wafer bends away fromblade core

d) Slice thickness

Figure 9

18

Blade start-up

The cutting edge of the newID saw blade has to adjustitself to the slicingconditions, which meansthat the cutting edgesurface structure,characterized by diamonddistribution, uneven platingsurface and slurry transportgrooves, needs adjustment.The adjustment isaccomplished during therunning-in or start-upperiod, which extends over a50 to 200 slice cuttingperiod. The feed rate isgradually increased to thefinal value over the start-upperiod; the slice surfaceindicates the start-upprogress.

The running-in of the bladestarts with a feed rate of0.591-0.787 inch/min (15-20mm/min). As soon as asatisfactory slice quality,preferably with a positivebow, is reached, the feedrate is then increased in0.197 inch/min (5-10 mm/min) increments until thefinal value is reached. Afterevery feed rate change, atleast 5 cuts need to be made.

If the ID saw blade issharpened before operation(initial dressing), werecommend using WINTER

Stone No. 8a (see alsosection on “Machinesharpening”, page 20).

Problem elimination

All actions that influence theID saw blade performance byeliminating targetdeviations are consideredcorrective measures.

In this catalog only a limitedoutline for defectelimination is possible, soonly the most importantdefects are listed.

The Trouble Shooting Guidelists the important defectsthe required correctiveaction.

Dressing and retensioningand are the most importanttechniques for correctingblade performance.

The exposure of the blade toa continuous force duringthe cutting cycle makes itlose some of its rigidity. Inorder to raise it to its formervalues, retensioned ofapprox. 100 µm byelongation of the ID may beneccessary.Blade dressing should beperformed with analuminium oxide dressingstone, never with a siliconcarbide stone. In additionthe dressing stick should beheld in a fixture. See“Dressing and sharpening IDsaws”, page 20.

Sawmarks– overall x x x x x x x x x x x– start of slicing x x– end of slicing x x xBow– convex x x x x x– concave x x x x x– taper x x x x x x xChipping– start of slicing x x– end of slicing x x xWafer breakagefrom mounting beam x x x x x xduring cutting x x x x x x

Cutt

ing

edge

irreg

ular

Cutt

ing

edge

dul

l

Cutt

ing

edge

too

shar

pIn

feed

rate

too

high

Blad

e ru

nout

too

larg

eSl

urry

exc

ess o

nbl

ade

Blad

e co

reda

mag

edCo

re te

nsio

n to

olo

wCo

olin

g flo

wra

teto

o lo

wCl

eani

ngflo

wra

te to

o lo

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olin

g flo

wra

teirr

egul

arCo

olin

g flo

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teto

o hi

gh

DefectDefectDefectDefectDefect

Possible causePossible causePossible causePossible causePossible cause

Table 3: Trouble shooting guideTrouble shooting guideTrouble shooting guideTrouble shooting guideTrouble shooting guide

19

Slice tracking system

Non-contact sensor systemsfor blade control andmonitoring, known as slicetracking systems, areavailable from the machinemanufacturers.Their purpose is to show theaxial deflection of the ID sawblade, thus in turn indicatingwhether the blade needsdressing or retensioning.In future, dressingprocedures will be fullyautomated. The followingcontrol cycle will be possible:the information given by theslice tracking system isconverted into either a

dressing pulse or a shut-offpulse, depending on the sizeof the deflection. Thenecessity of retensioning theID blade could likewise beindicated.

Safety precautions

An ID saw blade can failthrough excessive strain(blow, bump, twisting ofdressing stick, bladeovertensioning). Failure of asaw blade during the slicingoperations presents adanger to the operatingpersonnel. Because of thepotential danger of injury,the following safety

precautions should beobserved in the ID sawoperation:

• Wear safety glasses.

• Do not touch runningID saw blade.

• Use machinesharpening if possible.

• Remove broken slicefrom rear of blade onlywhen blade is at rest.

• Safe distance fromrotating saw foroperator 20 inches(50 cm).

ID saw Grit Blade Feed Coolant Mix Coolant CoolantNo. Materials type size speed rate type (%) cleaning flow Comments

(m/s) (mm/min) (l/h) (l/h)1 Aluminium nitride E D91 18 5-25 Water + 10 4 4

Syntilo R2 Aluminium oxide E D91 16 3-10 Water + 3 6 6 rotating

Meba SKNF3 Ferrite E D46 18 10-50 Water + 3 2-4 2-4

‘7IC AG“ ME 114 Gallium arsenide (315) D D46C 18 10-20 Water + 1 2-6 2-6

Syntilo R5 Gallium phosphide (315) D D46 18 10-20 Water + 1 2-6 2-6 special grit

Syntilo R6 Germanium D, B D46 19-21 30-70 Water + 1 2-6 2-6

Castrol 98117Water + 1 7-12 7-12 XK1

7 GGG D D46 18 10-20 Castrol 981178 Graphite D D91 21 250 Air9 Indium arsenide D D46 18 10-20 Water + 1 2-6 2-6

Syntilo R10 Indium phosphite D D46 18 10-20 Water + 1 6-8 8-12

Castrol 9811711 Lithium niobate D D46 18 20-40 Water + 1 2-6 2-6

Castrol 981112 Lithium tantalate D D46 20 3-10 Water + 3 6 6

Meba SKNF13 Optical glass (BK7) E D91 15 5-20 Mill-Kut 12 Co 10 8-10 8-10 special grit14 Quartz E D91 12 15-30 Mill-Kut 12 Co 10 8-12 8-12 special grit, rotating15 Quartz glass E D91 15 5~20 Mill-Kut 12 Co 10 8-10 8-10 special grit16 Samarium cobalt E D 911 18 10-30 Water + 3 -12 7-12

D46 MebaSKNF17 Sapphire E D91 . 19 1-5 Meba SKNF 3 10-12 10-12 rotating

Table 4: Guidelines for slicing of different materials

20

Other materials

ID slicing is currently mainlyused for slicing silicon. Thetrend toward expensivematerials and smallerdimensions makes thedescribed technologyincreasingly attractive alsofor slicing other materials.

Table 4 gives applicationguidelines for differentmaterials. New ways had tobe found in order to be ableto cut these materials (seepublications, footnotes onpage 4).

Dressing and sharpening IDsaws

1. Introduction

Despite optimization of corematerial, core thickness,cutting width, cutting layerand clamping system, one ofthe major problems that stillexists in ID saw bladetechnology is that the bladehas to be corrected duringoperation.

The most importantcorrection operationsinclude retensioning thecore and in particulardressing/ sharpening. It isvery important to note that

the optimization of thecutting result and blade lifeis directly dependent on theoperator’s skill in using thedressing stick at the righttime and with the righttechnique.

2. Fundamentals

During the slicing process ofmonocrystalline silicon (andother materials) with the IDsaw blade, the cutting layerchanges its surfacecharacteristics andgeometry.

More precise results onthese changes were found inexperiments carried out atthe WINTER company as partof a diploma thesis, and inpractical experience.

Figure 10: New ID saw Figure 11: Used ID saw

21

The cutting force FC can beanalyzed into its threecomponents FN, FT and FA

In an ideal slicing process,the workpiece is slicedabsolutely plane parallel,with only the forcecomponents FN and FT.

The change in topography(dulling of diamonds, changein chip space, roughersurface of bond) and the

Dressing and sharpening IDsaw blades

1. New saw blade

2. Cutting layer after 600 wafers

3. Cutting layer after dressing/sharpening

monitored with the aid ofthe Slice Tracking System.

This deflection ca:usessurface and geometricalerrors on the wafers.

The ID saw blade has to bedressed in order tocounteract the rise in cuttingforce components (FN) andthe deflection in axialdirection.

geometry of the cuttinglayer during the slicingprocesses may, how-ever, disturb the equilibriumof the system of forces. Theimbalance is caused by thecontinuous increase in forcesof FN and by the appearanceof an axial component FA.

This is expressed byundesired deflection of theID saw blade, which can be

Figure 12: Force distribution

Force distribution at point P

Fn: Normal forceFt: Tangential forceFa: Axial force

Fn

Ft

Fa

22

The dressing stick must becapable of:

- Generating new cuttingedges on the diamond;

- Setting back andcleaning the bond(creating chip space);

- Influencing thegeometric shape of thecutting layer.

These equirementsinevitably have an influenceon blade life.

3. Dressing / sharpeningmethods

Basically, there are twomethods:- Radial sharpening method(machine sharpening)- Axial dressing method(manual dressing)

3.1 Radial sharpeningmethod (machinesharpening)

With this method, the IDsaw blade cuts into orthrough the sharpeningstick. Radial sharpening ismostly carried out with afixture on the machine. Thisis mainly accomplished toreduce FN and FT. More thanthree sharpening passes perdressing cycle normally arenot advisable, as it is not

possible to achieve furtherimprovements in thetopography and geometry.Any further sharpening onlyreduces blade life.

Operating parameters forradial sharpening method:

Speed:Feed rate:Coolant supply:

Sharpening stick:For initial dressing -a hard stoneFor process dressing -a softer stone

State of sharpening stick:wet

Number of sharpeningpasses:

approx.3

3.2 Axial dressing method(manual dressing)

The axial dressing techniquecomes into considerationonly if the Slice TrackingSystem shows an axialdeflection outside of thespecified tolerance, or thegeometrical tolerances (bow,warp) are exceeded. In orderto counteract this, the IDsaw blade has to be dressedside opposite the deflectionwith an appropriate dressingstick.

If this dressing procedure isdone by hand, i. e. without adressing fixture, dressinghas to be done with greatcaution, in order to avoid

Figure 13: Process forces, influence of dressing

Parametersas slicingprocess

⎫⎫⎫⎫⎫⎬⎬⎬⎬⎬⎭⎭⎭⎭⎭

23

possible sources of errorsuch as:• Excessive changes in

geometry• Core contact• Layer displacementand also to avoid danger ofinjury to the operator.

For this dressing operation,the dressing stick is held atan angle of 45° to thevertical and 45° to the ID sawblade plane, in order to dressonly the radius. Dressing isdone tangentially to thecutting layer radius. Thedressing stick pass (withcross section 6x 6 mm)should last for approx. 3seconds).

In order to ensurecontinuous dressing, the

roof surfaces of the dressingstick should be symmetrical;the dressing stick should beturned 180° after eachdressing operation.

After the dressing operation,wait for at least 3 wafersbefore checking the grindingresult.

Parameters for the axialdressing method (manualdressing):

Speed:Coolant supply:

Dressing stickSoft stone (dimension6 x 6 x 100 mm)

Number of dressing passes:depending ondeflection, 1 - 3 times

At some time in the futurethe manual dressing will bereplaced by automateddressing.

4. Dressing/ sharpening stick

WINTER has various dressingsticks available. In the past,WINTER Stones 2, 6a and 7have been recommended forID sawing. Practicalexperience led to thedevelopment of dressing/sharpening sticks 8 and 8a.These have proventhemselves in practice,particularly in uniformity ofcutting edge generating andby good setting back of thebond.

The dressing/ sharpeningbehaviour of these WINTERStones 8 and 8a may bedescribed as more “gentle”compared with the previoustypes.

Overdressing is mostly notpossible, so that it is easierto control the process.

Questionnaire

The catalogue contains aquestionnaire see Annex.The answers to thesequestions will enableWINTER to give advice forthe solution of slicingproblems.

Figure 14: Dressing

Parametersas slicingprocess

⎫⎫⎫⎫⎫⎬⎬⎬⎬⎬⎭⎭⎭⎭⎭

24

SAINT-GOBAINSAINT-GOBAINSAINT-GOBAINSAINT-GOBAINSAINT-GOBAINDiamantwerkzeugeDiamantwerkzeugeDiamantwerkzeugeDiamantwerkzeugeDiamantwerkzeugeGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGSchützenwall 13-17D-22844 Norderstedt, GermanyTel.: +49 (0) 40 5258-0

Fax: +49 (0) 40 5258-215

Internet:http://www.winter-dtcbn.deE-mail:info-winter@saint-gobain.com

LG-Nr. 37 /06 e

Organizationfor the Safetyof Abrasives (oSa)

Certified toDIN EN ISO 9001:2000,No. QS-453 HH;DIN EN ISO 14001, No.EM-2129 HH;OHSAS 18001, No. S-2984 HH

25

QuestionnaireID saw blade application data

Company : Technical advice

Address : Quote

Order

Claim

Please provide below detailed information about intended slicing operation

1 Machine & wafer1.1 Machine & equipment1.2 Machine bow-setting (Limits) [µm]1.3 Workpiece material1.4 Material size [mm] and thickness [µm]2 Clamping & Tensioning2.1 Clamping force [Nm]2.2 Clamping screw characteristics2.3 Replacement of clamping screws2.4 Blade engraving (ingot-/wafer side)2.5 Tensioning procedure

(brief explanation)2.6 Runout [µm]2.7 Deflection weight [g]2.8 Maximum deflection [µm]2.9 Position of deflection measurement2.10 Elongation d/2 [µm]3 Cooling & cleaning3.1 Coolant medium3.2 Coolant ratio3.3 Coolant flow [l/h or cc/min]3.4 Coolant temperature [°C]3.5 Cleaning medium3.6 Cleaning flow [l/h or cc/min]3.7 Cleaning medium temperature [°C]3.8 Back flush flow [l/h]4 Sharpening & dressing4.1 Table dress stone specification4.2 Table dress stone dimensions [mm]4.3 Hand dress stone specification4.4 Hand dress stone dimensions [mm]4.5 Start dress procedure (initial dress)4.6 In-process table dress procedure4.7 In-process hand dress procedure4.9 Preventive dress procedure5 Operating5.1 Revolutions [rpm]5.2 Blade start-up process5.3 Production feed rate [mm/min]5.4 Retensioning [µm]