IC CMP And GMR Head CMP Are Not The Same Custom

IC CMP and GMR Head CMP are Not theSame – Custom Solutions are RequiredCMP User’s Group, Sept. 15 2010

Introduction CMP equipment designed for mainstream ICmanufacturing does not adequately support theneeds of Hard Disk Drive makers CMP equipment suppliers must address the uniquerequirements of the HDD industry in order to besuccessful Custom solutions produce better results:––––Improved process performanceHigher throughputLower cost of ownershipHigher yields

Contents Strasbaugh OverviewCMP Applications, Similarities and DifferencesGMR Head CMP ChallengesCustom Solutions that Work

Strasbaugh Background Founded in 1948– San Luis Obispo,With over 15,000 polishing and grindingsystems sold–California developed with world leading Semiconductor, LED,Optics, and Photonics companies, plus varioussubstrate manufacturersStrasbaugh became a public company in 2007– Strasbaugh is recognized around the world as aleader in precision polishing and grindingtechnologyMany design & development partnerships– Strasbaugh has over 60 years of leadership indesign and manufacturing of systems for precisionsurface preparation including CMP, polishing, andgrindingcurrently trading on the OTC bulletin board underthe symbol STRB.OBHeadquarters are in San Luis Obispo,California–with a world-wide sales and support network

CMP and Polishing SystemsSTB P300nTegritynHancenSpirenFinityProductWafer SizesAutomationDescriptionsSTB P300150-300mmFull3 Table, 2 Spindle, DIDO/DIWOnHance200-300 mmSemi1 Table, 1 Spindle, DIWOnSpire75-200 mmSemi1 Table, 1 Spindle, DIWOnTegrity100-200 mmFull2 Table, 2 Spindle, DIWOnFinity100-200 mmFull2 or 3 Table, 2 or 3 Spindle, Wax-mount Polisher

Grinding SystemsnTellectnGenuitynCompassProductWafer SizesAutomationDescriptionsnTellect100-200 mmFull4 Cassette, 2 Work Chuck, 2 Grind Spindle,Infeed Rotary Surface GrindernGenuity75-200 mmFull or Manual2 Cassette, 1 Work Chuck, 1 Grind Spindle,Infeed Rotary Surface GrindernCompass100-200 mmFullPrecision Edge Profiler

Driving Future GrowthStrasbaugh continues to help drive technology forward– by investing heavily in new products and leading edgetechnologies for strategic, high growth industriesSamsungATTNASAACR AquaLinkSolid State ElectronicsBosch inertial sensorThese industries include:– Semiconductor CMP– LED– TSV– MEMS– GMR Head CMP– Silicon Prime Wafer– Compound semiconductor– Wafer reclaim– Failure Analysis– Precision Optics

CMP ApplicationsSimilarities and Differences

CMP Applications CMP is critical to a broad range of applicationsincluding:–––––GMR and MR HeadSemiconductor ICThrough Silicon Via (TSV) or 3D ICMEMSLED Common ing and erosionEdge exclusionRemoval rateDefectivity One solution does not fit all

Gigantic Magnetoresistive HeadDetailed structure of aGMR head assembly. Thearm/slider/head structure atthe top is actually onlyabout ¼” (6.3 mm) long.Original image IBM Corporationfrom www.pcguide.comCross sectional view showing multilayereddesign and required CMP steps. A typicalsuch “sensor stack” is about 40 nm thick. Atypical wafer will have a capacity of about20,000 such heads.Image from www.electroiq.com

MicroelectricomechanicalSystems (MEMS)www.sensormag.comThe resonant ring at the heart of the Silicon SensingSystems gyro is shown here as an SEM image.Silicon Sensing Systems, a joint venture betweenSumitomo and British Aerospace (BAE), has broughtto market an electromagnetically driven and sensedMEMS gyro. A permanent magnet sits above theMEMS device. Current passing through theconducting legs creates a force that resonates thering. This Coriolis-induced ring motion is detected byinduced voltages as the legs cut the magnetic field.www.segway.com

Through Silicon Via (TSV)Via-first integration forms theTSVs in the wafer fab duringfrontend processing, and the viasare generally smaller, rangingfrom 1-10µm dia. and 10-60µm indepth.Via-last integration takes place inassembly and packaging after waferprocessing is completed and typicallycreates fewer, larger vias, 20-50µmin dia. and 50-400µm deep.All images from www.electroiq.comThe market forces driving 3D IC developmentinclude consumer demand for greaterfunctionality in smaller devices, enhancedperformance in advanced computing systemsand, ultimately, lower cost. Thinned chipsconnected by TSVs can reduce the height andwidth of the packaged chip stack relative tocurrent wire bonding technologies.

Light Emitting Diodes (LEDs)www. pge.comwww.statusreports.atp.nist.govThe typical substrates used inLED manufacturing, i.e. SiliconCarbide or Sapphire, are usuallychosen for their insensitivity toincreased operating temperatures(dissipation coefficient), resistanceto most chemicals and radiation,power output, and high fieldstrength. Some LEDs are beingmade using monocrystaline siliconas the substrate.www.statusreports.atp.nist.gov

CMP Applications:Similarities and hallengesIC CMPVery dense 65 nm downto 22 nm andsmaller Metal devices Cu, W plugs ILD STI Cu Al W TiN TaN 4000 Å (or0.4 microns) 10 or more metallayers 6% - 8% WIWNU(three sigma) Multitude of varioussmall structures WIW dishing 100 Å Defectivity CoO Throughput Dishing/Erosion End Point Low downforcesGMRHead Moderatelydense Densityincreasingevery year Large, up to80µm -100µm constant sizereductioneffort Copper coils AlTiC up to 35µm ofAl2O3 overcoat 6µ or lessfor NiFe 5Kµm -10Kµmfor other filmtypes WIW dishing 40 Å(std deviation) Combination ofdissimilar materialhardnesses ofvarious structuresand devices. Substrate bow/warp TTV of the AlTiCsubstrates results sensitiveto pad surface Wafer flats Final thicknesscontrol Pre CMP film NU corrosionMEMSOften notdense Numerousstructuretypes Small wafersbut largefeatures andstructures Silicon Oxides Nitrides Titanium Copper PolysiliconCould beextreme up toseveral tensof microns. Large structures Thick films Large open spaces Small wafers;sometimes one largedevice per wafer Wide variety offeatures, patterns Need excellentplanarization Very low downforces areimportantTSV2µm x 2µm(via first) to30µm x100µm ormore (via last)up to 400µmThis processexposesnarrow butdeep trenchesfor multichipinterconnectsUsuallysilicon butalso couldinvolve Al,Cu, Nitrides20µm – 50µm(or more) ofsiliconExpose all of thetrenches in order tofacilitate chip-to-chipmulitlayerinterconnections Thin wafermounted on glasssubstrate Combination ofgrinding &polishing Process CoO MechanicalstressLEDN/AN/ASubstrate isSiC, Si, orSapphireHundreds ofmicronsPost-grind polishingbalances stress, andfacilitates improvedbrightness Thinning(substrate) Al2O3 NiFe Cu Tantalum Rutheniumprocess Bow, warp Handling

Challenges in GMR Head CMP Total thickness variation (TTV) of AlTiC substrates– TTV can vary from 0µm to 5µm wafer to wafer– Substrates can be bowed, warped, concave or convex CMP results are sensitive to pad surfaceWafer flatsFinal thickness controlPre-CMP film non-uniformityCorrosion of exposed metal on the head deviceMost IC CMP advancements take place at 300mmwhile the bulk of GMR Head manufacturing is beingdone on 150 to 200mm wafers

Strasbaugh’s Custom Solution Our latest generation CMP system, the STB P300 has been designed to meet the unique needs of GMR HeadCMPViPRR Wafer Carrier and Multi-Zone Back PressureControl––Available for 125mm, 150mm, 200mm and 300mm wafersBetter uniformity control & reduced edge exclusion Low downforce process capability–Minimizes dishing and erosion Precision Pad Conditioner–Maintains ideal pad roughness to control uniformity and minimize dishingand erosion Optical Endpoint–Prevents over and under polish Post CMP Cleaning–Improves defectivity and minimizes corrosion of exposed metal on thehead device Wafer surface grinding prior to CMP for overcoat removal

STB P300-DS A Better Choice in CMP

STB P300 CMP SystemIntroduction Built for flexible process and high volumeproduction15 to 50% smaller footprintthan other 300mm highvolume production CMPsystemsIndependent spindlemovement allows flexibleprocess flows through thetoolAuto Force Calibration reduces setup time and thenumber of test wafersrequired2 spindle, 3 table designfurther reduces setup time

STB P300 Introduction Cont. Industry-proven,integrated cleaningand state-of-the-artdefectivity control 125, 150, 200, and300mm wafer sizecapable –approximateconversion time: 16hours CMP system andcleaner can operateindependently fromone another

STB P300 Overhead ViewRinseStationPolishTable #2PolishTable #3Spindle/Carrier #1BrushBoxes#’s 1 & 2TransferStationDry 79.5”202 cmElectricalCabinetsSpindle/Carrier #2PolishTable #1LoadStation165.4”420 cmUnloadStationWet WaferhandlingrobotSpin RinseDryerHgt 89” or 226 cmWgt 12,500# or 5682 kg

Independent Spindle Motion Spindles move independently from one another, enabling flexible process flows through the toolThe P300 performs serial and parallel processing for one,two, or three table polishing processesAllows polish times to vary for each wafer – providing alevel of process optimization and flexibility available onlywith the P300

Process Technologies & Features

150mm Blanket AluminaProcess Results (STB P300) Wafers:– 150mm AlTiC substrate with blanket alumina CMP System: STB P300 Carrier: ViPRR I, Button Style Consumables:– IC1000/Suba IV, K Groove– Cabot, MH 210Wafer12345Avg.WIWNU(%) (61point contour) Rate 0105WIWNU(%) (55point diameter,5mmEE)2.42.32.34.14.03.0Rate (A/min)1007297629988102591016710050

150mm Blanket AluminaProcess Results (nTegrity 6DS-SP)

ViPRR Carriers “ViPRR” Variable Input Pressure Retaining RingUtilizes solid backingplate with insert filmrather than membraneCombines with MultiZone Back Pressure tooptimize uniformityresultsResults in betterexclusion at the wafer flat(5mm edge exclusion)Proven in production fora wide range ofapplications since 1997– GMR Head, MEMS, TSV,STI, W, TEOS, SOI

ViPRR Carrier Features Angular pick-up prevents “suction-cupping” at the polish padVIPRR retaining ring precompresses the polish pad nearthe wafer, reducing the possibility of a thick-edge polish– Grooved and Non-grooved– Designed for flat retaining ring wear for longer ring life Few moving parts– Improves reliability, minimizes carrier maintenance, and extendsprocess stability– Re-assembly is made easy by engraved alignment marks Corrosion resistant materials– Titanium, SS, Advanced Polymers Variety of gimbal choices– Choose the gimbal that optimizes process results and provides alarge vibration-free window

Improved Uniformity with ZoneBack PressureReduced Diameter ViPRR II Carrier - Tungsten WaferStandard. vs. Zone Back Pressure ComparisonDiameter Scan (5mm Edge Exclusion)3500WITH ZONE BACK PRESSUREOuter Edge Zone Back PressureWIWNU 2.9 %3000Uniform PolishingRemoval (A)2.8% 1 sigma25002000WITHOUT ZONE BPStandard Back PressureWIWNU 11.9 %Center Fast Polishing1500Positive Back 25.0Location (mm)Slot 23Center Slow PolishingNegative Back PressureSlot 2440.055.070.085.0

Low Downforce Control P300 is designed to accurately provide a wide rangeof polish forces (25 to 750 lbs.) Low force range calibration data from StrasbaughP300 CMP Tool Force is accurate to within 1% down to 10lbs

Precision Pad Conditioning Programmable control of sweep segment dwell time, force, and rotational speedDwell time and downforce are input to control 23conditioning zonesZones can be used to create a specific pad profileConditioning arms for each of the primary polish tablesInsitu and/or exsitu pad conditioningLow profile head maximizes throughputClosed loop downforce control holds tighter toleranceenabling ultra low-downforce conditioningDown force range:0.5 to 20 lbs.

Precision Force ControlExample Precision Pad Conditioner calibration data showsan average variance of only 0.3% between thetarget and actual downforce