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 20Questionaire 24

Contents

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Introduction

The ID saw blade consists ofa thin circular steel core,which is tensioned at itsoutside diameter (OD) andhas its diamond cutting edgeelectrodeposited on theinside 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 8 1/8 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 and origi-nal equipmentmanufacturers on furtherdevelopments of ID sawingtechnology.

Considerable experience isrequired in the selection andproper usage of ID sawblades. The present catalogcontains helpful informationbut does not claim to answerall arising questions. Forfurther information pleasecontact the WINTERcompany or your 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.Statistical process controls(SPC) are conducted in orderto insure uniform quality.

WINTER diamond ID saw blade development

Publications.Publications.Publications.Publications.Publications.Cutting Sapphire with Annular SawBlades, Industrial Diamond Review,37 (1977), No. 2

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

Diamantwerkzeuge für dieElektronikindustrie (Diamond Toolsfor the Electronics Industry),Feinwerktechnik und Meßtechnik1985, No. 3

Schärfen 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 diamonds andbond of the ID saw blade)Diploma thesis by Michael Kleinert,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 asamarium-cobalt slicingprocess, involving theoptimization of slicingparameters 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 21.

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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 D46,D46B and D46C.

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

Fig. 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 there is not just ameasuring of nickel by itself.Thus it is important not toneglect the influence of thegrit.

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.Infuence of concentrationInfuence of concentrationInfuence of concentrationInfuence of concentrationInfuence 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 become establishedfor practical operation insilicon 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 standaed 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 Core material3 Core material3 Core material3 Core material3 Core material

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),

Fig. 2: Quality assurance during production

Coil Square Core Blade

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

delivery In roll direction core production (SPC)- Define test - Visual inspection - Drilling - Saw inspection

procedures (color change, - Inspection on - Customer- Perform incoming gooves, dents, special fixtures certificates

inspection etc.) (centering bores

Sketch

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giving the following benefitscompared with theconventional manufacture:

- 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) which is analogousto the B-type. If necessary,the blades may have to beadapted to the customersprocess 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 accuratelyIn order to ensure good,constant wafer quality linkedwith long blade life, the kerfloss is reduced, particularlyin the startup phase of theblade. This is reflected inhigher yield and higherproductivity.First conclusions can bedrawn on the applicability ofthis new type from practicaltests. The results led to the

latest development of theLB-type. This type wasdeveloped specially for thin-kerf applications. It featuresno-problem startingbehaviour, and permitscontinous operation. Due tothe production process theLB-type has an X-dimensionof 0,13mm (the D-type has anX-dimension of only0,10mm), thus an incraese of

lifetime of approx. 20% canbe expected.

4.2. Cutting widthimprovements

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

Fig. 4: Tolerances

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

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

Fig. 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 their cores,and are hard to handle in theuntensioned state due totheir low rigidity.WINTER recommends that IDblades be kept in their origi-nal package until usage.Great care should be taken toavoid kinking blades whenhandling them. In the eventof 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 thefollowing requirements:a) Stepless cutting speed

regulation of ingot crossfeed into the blade

cutting edgeb) Stepless speed control

for achieving theoptimum bladerotational speed neededfor cutting differentmaterials

c) Indication and control ofcoolant flow

d) Automatic slice removal.e) Slice tracking systemf) System for automatic

deflection-correction

Mounting of the ID sawblade

Expert mounting andtensioning are essential forthe proper functioning of theID blade.

Improper blade mountingcan lead to the followingproduction problems:

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

Pict. 1: Remove clamping ring bleedscrew and metal tensioning ring.Reinsert bleed screw and tighten itClean and degrease clamping ringsurface.

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

Pict. 4: Clean and degreaseclamping areas. -Clean bladetensioning support area and coverthe area with a thin coat oflubricant.

Pict. 2: Clean and degrease theblade clamping areas (on each side)and position the blade on theclamping ring guide pins.

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.

Pict. 5: Positioning of elongationmeter in the ID of the blade.

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Pict. 8: Clean and degrease upperclamping ring.

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

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

Pict. 11: Tighten clamping screwscrosswise using an Alien wrench.Generally the clamping ring screws(M6 property class 12.9) aretightened with a torque wrench to15 Nm. To avoid screw failure,screws should be replaced at everyblade change.

Pict. 12: Clean tensioning ring andcover it with a thin coat of grease.

Pict. 14: Set up a dial gage andcenter blade ID by tightening 4clamping screws crosswise.Accurate centering at this time isthe basis for the final blade set-upand centering accuracy. Tensionblade and adjust blade run-outduring this operation according toTable 2.

Obtain the proper elongation valuefrom Table 2.

Pict. 13: Mount clamping rings withsaw blade on top of tensioning ring.

Pict. 15:Measurebladedeflection asshown onpage 13. Ifbladedeflection isbelow thevalue given inTable 2

further tensioning of the blade isneeded.

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)

Pict. 6: Clean and degrease lowerclamping ring.

Pict. 7: Clean and degrease bladeclamping area. Place blade inclamping position on lowerclamping ring without touching thecleaned and degreased clampingarea.

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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 receives therequired stability throughtensioning. Proper bladetension and stability are themost important factors forgood slice quality and sliceproperties.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 various deflectiondata should be attained as afunction of the specific IDsaw, depending onproduction process.

The following points must bedefined:a) ID enlongationb) 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 ID bladeis measured at three points,120° apart. The distancebetween the measuringpoint and the ID is 5 mm, (seeFig. 19).c)Deflection forcec)Deflection forcec)Deflection forcec)Deflection forcec)Deflection forceThe deflection measuring forinternal tensioning testsafter the production processis done with a test force of 1.7N ± 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 on thelength measuring unit.

The differences between thethree readings may notexceed 2 µm. If there is agreat difference between thereadings the tension in theblade 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 lowervibration level in the slicingprocess.

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

The coolant’ additivesgenerally used aresurfaceactive fluids andsynthetic coolant oils. Acoolant additive shouldalways be used unlessprocess difficulties arethereby 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 nozzles shouldbe positioned in such a waythat the coolant flow isevenly split. An even split ofthe coolant stream willassure 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. The IDelongation can give anindication about the rigidityof the ID blade; however, thisis only an indirect clue, sincechanges in saw blade designaffect the rigidity of theblade, and thus with equal IDelongation the blade willdevelop different values forthe restoring force. If a fixedvalue of ID elongation is usedfor blade stability as astandard without deflectionmeasurement, a variation inthe performance of the sawblades must be tolerated.Loss of blade rigidity will beexperienced over the life ofthe blade. Retensioningtowards the end of blade lifenormally is notrecommended

At the same time as IDelongation, radial run-out isalso measured. The radialrun-out should be as small aspossible, and at any rate notmore than 0.0008 inch (0,02mm).

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 comparison forthe user.

Crystal mounting

Many different mountingmaterials are used e. g.

graphite, carbone fiber,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 betweencrystal-epoxy-mountingbeam. As soon as the epoxyis hardened, the excessepoxy is removed to avoidany gum-up of the cuttingedge.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. With

increased material diameter,slice tolerances need to belooser.Figure 22 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 forbow in 90% of the slices thatare affected by bow. Elimina-tion of this defect can beaccomplished by etching (seeFig. 23a).b) Wandering of the bladeduring slicing.This defect is caused by lowblade tension and / or dullblade (see Fig. 23b).

A distinction is madebetween positive and negati-ve bow (see Figs. 23c and23d). The notation positive ornegative has been derived

Slice thickness Slice taper

Slice bow Slice chipped

a b

a-b

Fig.: 8

17

from the positive or negativeslice contour.

With the positive bow thewafer moves away from thecenter; for this reason nofriction is caused betweenwafer and crystal. In this casethe slice cannot be pulled off,thrown or broken by theblade (see Fig. 23c).

With negative bow the waferbends toward the blade.Friction forces can developbetween wafer and blade,and they can be of greatermagnitude than the forcethat holds the slice to theepoxy. In this case the waferwill be pulled off the epoxyand broken.

(For elimination of thesedefects see Trouble ShootingGuide)

a) Bow caused by surfaceirregularity

b) Cut waferbendstowardblade core

c) Positve bow

Cut wafer bends away fromblade core

d) Slice thickness

Fig.: 9

18

Blade start-up

The cutting edge of the newID saw blade has to adjustitself to the slicingconditions, which meansthat the cutting edge surfacestructure, characterized bydiamond distribution,uneven plating surface andslurry transport grooves,needs adjustment. Theadjustment is accomplishedduring the running-in orstart-up period, whichextends over a 50 to 200slice cutting period. The feedrate is gradually increased tothe final value over thestart-up period; the slicesurface indicates 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 in 0.197inch/min (5-10 mm/min)increments until the finalvalue is reached. After everyfeed rate change, at least 5cuts need to be made.

If the ID saw blade issharpened before operation(initial dressing), werecommend using WINTERStone No. 8a (see alsosection on „Machinesharpening“, page 23).

Problem elimination

All actions that influence theID saw blade performance byeliminating target deviationsare considered correctivemeasures.

In this catalog only a limitedoutline for defectelimination is possible,therefore only the mostimportant defects are listed.

The Trouble Shooting Guidelists the important defectsand the required correctiveaction.

Dressing and retensioningand are the most important

techniques 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 addition thedressing stick should be heldin a fixture. See Dressing andsharpening ID saws“, page22.

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 xWafer breakageduring cutting x x x x x x

Cutt

ing e

dge

irreg

ular

Cutt

ing e

dge d

ull

Cutt

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dge t

oosh

arp

Infe

ed ra

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ohi

ghBl

ade r

unou

t too

larg

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urry

exce

ss o

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ade

Blad

e cor

eda

mag

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re te

nsio

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low

Cool

ing f

low

rate

too l

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eani

ng flo

wra

teto

o low

Cool

ing f

low

rate

irreg

ular

Cool

ing f

low

rate

too h

igh

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 the future the dressingsprocedures 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 a dangerto the operating personnel.Because of the potentialdanger of injury, the

following safety precautionsshould be observed in the IDsaw operation:

• 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 FlowNo. Materials type size speed rate type (%) cleaning cooling 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 presently 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 the coreand mainly dressing/sharpening. It is veryimportant to note that the

optimization of the cuttingresult and blade life isdirectly 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 and

geometry.More precise results on thesechanges were found inexperiments carried out atthe WINTER company as partof a diploma thesis andpractical experience.

Figure 10: New ID sawFigure 10: New ID sawFigure 10: New ID sawFigure 10: New ID sawFigure 10: New ID saw Figure 11: Used ID sawFigure 11: Used ID sawFigure 11: Used ID sawFigure 11: Used ID sawFigure 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 causessurface 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. Theinbalance 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

Fig. 12: Force distribution

22

The dressing stick must becapable of:

- Generating new cuttingedges on the diamond;

- Setting back and cleaningthe bond (creating chipspace);

- Influencing thegeometric shape of thecutting layer.

Due to these requirements,there is an inevitablyinfluence to the blade life.

3. Dressing / sharpeningmethods

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

3.1 Radial sharpening method(machine sharpening)

With this method, the ID sawblade cuts into or throughthe sharpening stick. Radialsharpening is mostly carriedout with a fixture on themachine. This is mainlyaccomplished to reduce FNand FT. More than threesharpening passes perdressing cycle normally arenot advisable, as it is notpossible to achieve further

improvements 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 stone for in-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 ID sawblade has to be dressed onthe other side to thedeflection with anappropriate dressing stick.

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

Fig. 31: Process forces, influence of dressing

Parametersas slicingprocess

���

23

possible sources of errorsuch as:• Excessive changes in

geometry• Core contact• Layer displacement and

also to avoid danger ofinjury to the operator.

For this dressing operation,the dressing stick is held atan angle of 45° to the verticaland 45° to the ID saw bladeplane, in order to dress onlythe radius. Dressing is donetangentially to the cuttinglayer radius. The dressingstick pass (with cross section6x 6 mm) should last forapprox. 3 seconds).

In order to ensurecontinuous dressing, theroof surfaces of the dressing

stick 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

Forward-looking the manual

dressing will be replaced byautomated dressing.

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 the uniformityof cutting edge generatingand by good setting back ofthe bond.

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 easier tocontrol the process.

Questionnaire

The catalog contains aquestionnaire on page 24.The answers to thesequestions will enable WIN-TER to give advice for thesolution of slicing problems.

Fig. ????????

Parametersas slicingprocess

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24

SAINT-GOBAINSAINT-GOBAINSAINT-GOBAINSAINT-GOBAINSAINT-GOBAINWINTER DiamantwerkzeugeWINTER DiamantwerkzeugeWINTER DiamantwerkzeugeWINTER DiamantwerkzeugeWINTER DiamantwerkzeugeGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGGmbH & Co. KGSchützenwall 13-17,D-22844 NorderstedtP.O.Box 2049,D-22841 NorderstedtTel.: +49 (0)40-52 58-0Fax: +49 (0)40-52 58-215Internet:http://www.winter-dtcbn.deE-mail:info-winter@saint-gobain.com

LG-Nr. 37 /01 e

Certified acc. toDIN EN ISO 9001Certifcate No.QS-453 HH

Certified acc. toDIN EN ISO 14001Certifcate No.EM-2129 HH

25

QuestionaireID saw blade application data

Company : Technical advise

Address : Quote

Order

Claim

Please provide below detailed information about intended sclicing operation

1 Machine & Wafer1.1 Machine & Equipment1.2 Machine Bow-Setting (Limits) [µm]1.3 Material of workpiece1.4 Material size [mm] and thickness [µm]2 Clamping & Tensioning2.1 Clamping force [Nm]2.2 Clamping screws property [class]2.3 Replacement of clamping screws2.4 Blade Engraving (Ingot-/Waferside)2.5 Tensioning procedure

(brief explanation)2.6 Run out [µm]2.7 Deflection weight [g]2.8 Permissible target deflection [µm]2.9 Position of deflection measuring2.10 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 [min-1]5.2 Blade start-up process5.3 Production feed rate [mm/min]5.4 Retensioning [µm]