Cyclotene Advanced Electronics Resins CH Si CH CH

Cyclotene* Advanced Electronics Resins CH Si CH CH 3 O 3 Si 3 CH 3 Process Description / Flow & Equipment Coating Exposure Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Development 1

BCB PRODUCT FEATURES CH 3 Si CH 3 O CH 3 Si CH 3 v LOW LOSS AND LOW DIELECTRIC CONSTANT v HIGH TEMPERATURE CAPABILITIES v HYDROPHOBIC v NO VOLATILE BY-PRODUCTS v EXCELLENT DIELECTRIC PROPERTIES v EXCELLENT PLANARIZATION v WATER FREE CHEMISTRY WITH LOW WATER PICK -UP v EASY PROCESSABILITY Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 2

DIELECTRICS PRODUCT RANGE 1 ELECTRONIC GRADE BCB DIELECTRICS : XU 71918, CYCLOTENE* 3022 2 ELECTRONIC GRADE PHOTOBCB DIELECTRICS : CYCLOTENE* 4024, 4026 3 SEMICONDUCTOR GRADE DIELECTRICS : Si. LK* * Trademark of The Dow Chemical Company Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 3

ANCILLARY PRODUCT RANGE 1 SILANE ADHESION PROMOTER AP 3000 2 EBR, BACKSIDE, CLEANING SOLVENT, STRIPPER T 1100, STRIPPER A 3 DEVELOPPERS (PUDDLE & IMMERSION) DS 2100, DS 3000 * Trademark of The Dow Chemical Company Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 4

BCB Chemistry R Benzo Cyclo Butene (Chemical group) Di. Vinyl Siloxane bis-Benzocyclobutene DVS-BCB (Monomer) 3 CH CH 3 Si CH 3 O 3 CH Si CH 3 BCB Prepolymer (Commercially Available Solution) CH 3 O CH 3 Si O Si 3 CH CH 3 Si CH 3 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 CH 3 Mesitylene CH 3 5

Curing Chemistry of DVS BCB CH 3 Si O CH 3 D CH 3 . . . Si CH 3 Diels - Alder Thermal Polymerization 150°-300°C DVS BCB Prepolymer CH 3 Si O Si CH 3 CH 3 S i CH 3 O CH 3 S i 3 CH 3 O Highly Crosslinked Network Tg > 350 °C CH 3 S i CH 3 Si O Si CH 3 CH 3 O Si Si C H 3 CH 3 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Si CH 3 6

BCB Curing Time-Temperature-Transformation Diagram Reaction Rate 10 X Slower after Vitrification Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 7

Properties of Cyclotene* 4024 -40 v v v v SOLIDS CONTENT SOLVENT VISCOSITY FILM THICKNESS PHOTO-SENSITIVITY DIELECTRIC PERMITTIVITY, e< 2. 7 DISSIPATION FACTOR BREAKDOWN VOLTAGE (Volts/cm) CTE (Ppm/°C, 25 -300°C) Tg (°C) ELONGATION (%) WATER ABSORPTION (% @ 85 % RH) STRESS @ RT (MPa) THERMAL STABILITY (1% Wt. Loss/Hr. ) ALPHA BARRIER SODIUM BARRIER Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 40 % MESITYLENE 350 c. St 4 - 8 µm i-LINE / 365 nm 0. 0008 4 X 106 52 > 350 10 < 0. 2 < 30 350 °C HIGH YES 8

Water Absorption and Desorption of Cyclotene* 3022 Films WEIGHT UPTAKE (%) 0. 14 81 % RH 0. 12 0. 1 0. 08 0. 06 0. 04 0. 02 6 % RH 0 -0. 02 -200 0 200 400 600 800 1000 1200 1400 Time (s) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 9

Block diagram for Photo-BCB process flow Clean Promoter spin /dry Cyclotene coat HP bake Stripping AP 3000 Cyclotene 402 X T 1100 UV Exposure Primary Stripper A Pre-develop bake Develop Post-develop bake DS 2100 DS 3000 Cure Descum Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 10

Required Process Chemicals 1 AP 3000 Silane Adhesion promoter 2 Cyclotene* 4024 - 40 or Cyclotene* 4026 - 46 3 -7 micron films 3 T 1100 Mesitylene for EBR / Backside 4 DS 2100 or DS 3000 Single wafer puddle development 5 Primary Stripper A Rework 7 -14 micron films Batch development Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 11

Equipment: Part 1 1) Storage Cyclotene @ -15°C in freezer for safety stock storage. In fridge at 0 - 5 °C for use in production. Solvents (AP 3000, T 1100, DS 2100, DS 3000, Stripper) are stable > 24 months @ RT 2) Clean O 2 (F) Plasma / Megasonic / QDR / SRD (If wafers stored in boxes over longer time or after metal process. Same tool as descum. ) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 12

Equipment : Part 2 3) Coat Spin coater (track or cluster) Spinner (one bowl) & 1 hotplate minimum (< 150 deg C, ambient) 4) Expose Mask aligner or projection / stepper tool (Broadband) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 13

Equipment : Part 3 5) Develop Option 1 : Puddle develop on track • 1 Hotplate (for reset), one spin bowl, 1 hotplate (< 150 deg C, ambient) Option 2 : Batch develop using solvent wet benches • Circulation oven (~60°C for reset) • DS 3000 develop bath • DS 3000 Rinse bath • SDR Option 3 : Batch develop Dry-in Dry-out • Circulation oven (~60°C for reset) • DS 3000 Solvent Develop tool (Rena) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 14

Equipment : Part 4 5) Rework Primary Stripper A bath (T 1100 Mesitylene bath optional) IPA bath, QDR, SDR 6) Cure Clean room convection oven (N 2, <100 ppm O 2, RT -> 250 deg. C) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 15

Equipment : Part 5 7) Pad Clean Parallel plate plasma etchers (SF 6 or CF 4 or NF 3 with O 2) 8) Various inspection tools Inspection Microscope, CD control Film thickness measurement / Profilometer Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 16

Cyclotene Spin Coating BCB Track / Cluster Minimum Configuration - One Spin bowl (for Promoter and BCB) - One Hotplate Chemical supply lines: AP 3000 : N 2 pressure dispense, 0. 2 µm filter Cyclotene* : pump (viscosity (4026) < 1150 c. St T 1100 Mesitylene : N 2 pressure dispense, 0. 2 µm filter (EBR, Backside, bowl rinse) Waste flow : Halogen free solvents, not miscible with resist waste. Suss ACS 200 Spin Cluster (@ Fraunhofer IZM Berlin) Other coaters processing BCB: TEL, DNS, MTI /S 3, Solitec, SVG. . . Typical Spin Recipe 1) Dispense AP 3000 2 sec @ 50 rpm 2) Dry AP 3000 30 sec @ 2000 rpm (optional 60 sec @ 150°C bake for difficult surfaces) 3) Dispense Cyclotene 402 X static or radial recipe 4) Spread (for open coaters) 5 - 10 sec @ 500 rpm 5) Spin 30 sec @ 1000 - 4000 rpm, (optionally with BSR) 6) BSR/EBR 5 sec @ 1500 rpm, 5 sec dry @ 1500 rpm 7) Hotplate bake 60 - 90 sec @ 70 - 110 ° C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 17

Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 18

Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 19

Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 20

Cyclotene* 4024 -40 Spin Curves on ACS* 200 * Trademark Karl Suss Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 21

Cyclotene* 4026 -46 Spin Curves on ACS* 200 * Trademark Karl Suss Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 22

Cyclotene* 4024 -40 Thickness Distribution on 8 inch Wafer vs. RPM / Spin Time 3 = 0. 79 µm 4 5 6 1 2 3 9 8 7 Position 3 = 0. 27 µm 3 = 0. 42 µm 3 = 0. 24 µm Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 23

Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 24

Cyclotene* 4026 Via Shape vs. Exposure mode Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 25

Cyclotene* 4026 Exposure Latitude vs. Base Metal Texture and Reflectivity Exposure dose (sec) (i-line) Exposure dose (m. J/cm 2) (i-line) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 26

Metal Reflectance Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 27

Photo. BCB Develop 1) Puddle DS 2100 Puddle Develop on Track Configuration : - Reset Hotplate (~70 °C) / eventually cool plate - Spin bowl with optional N 2 blow drying - Dry Hotplate (~100 °C) Chemical supply line : DS 2100 Developer, filter Waste flow : Halogen free solvents Typical Puddle Develop Recipe : 1. Hotplate prebake 60 sec @ 60°C 2. Dispense DS 2100 2 - 4 sec @ 50 - 100 rpm 3. Static develop (1. 4 x Run time) - 10 sec @ 0 rpm 4. Rinse with DS 2100 10 sec @ 500 rpm 5. Dry wafer 20 sec @ 2000 rpm 6. Hotplate bake 60 sec @ 80 - 120 °C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 28

Photo. BCB Develop Puddle Block Diagram Predevelop Hotplate Bake Cool Deposit DS 2100 on Wafer Puddle for Fringe time + 30% to 50% - 10 seconds Rinse 10 seconds with DS 2100 at 500 rpm Spin dry 30 seconds at 1000 - 3000 rpm Hotplate Bake Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 29

Photo. BCB Develop Puddle Block Diagram - Alternative Method Predevelop Hotplate Bake Cool Deposit DS 2100 on Wafer Puddle for Fringe time + 30% to 50% Overdevelop Rinse 5 seconds with DS 3000 at 500 rpm Spin dry 30 seconds at 1000 - 3000 rpm Hotplate Bake Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 30

Prebake of Photo-BCB Development Time (Immersion) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 31

Develop Time vs film aging at RT Hotplate bake after spin 90 seconds 70 °C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 32

Cyclotene* 4024 -40 Develop Time Control Aged Films Hotplate reset 60 seconds 75°C Reset Films Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 33

Photo. BCB Develop 2) Batch Immersion DS 3000 Immersion Develop in Tank Configuration : - Develop Tank (30 -35 °C) +/- 0. 5 C, circulation & filtering - Rinse Tank(s) (RT, circulation & filtering) - SRD N 2 Spin Dry connected to solvent waste Chemical supply lines : DS 3000 Developer Waste flow : Halogen free solvents (Courtesy of Strand Interconnect) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 34

INFLUENCE OF HOTPLATE BAKE ON DEVELOP TIME Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 35

Cyclotene* 4024 -40 Thickness Loss During Development in DS 3000 @ 32°C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 36

Cyclotene* 4024 -40 Thickness Control During Development in DS 3000 @ 32°C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 37

Cyclotene* 4024 -40 Develop Time Control Circulation Oven Batch Reset Aged Films Reset Films Conditions : 5 minutes at ~ 60 °C Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 38

Photo. BCB Develop Options 3) Batch Spray Develop DS 3000 Spin & Spray Configuration : - Warm Spin/Spray Develop - Cold Rinse - SRD Throughput : Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 < 30 min / 25 wafers 39

Photo. BCB Curing Time-Temperature-Transformation Diagram Hardcure Softcure Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 40

Photo. BCB Cure Types : Blue-M, Despatch, YES, furnaces Configuration: Class 100, N 2 flow (<100 ppm O 2) Facilities: AC / N 2 / Cooling water Typical Hardcure Temperature Profile (Courtesy of Strand Interconnect) Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 41

Plasma Descum A plasma clean is needed to remove a thin layer of BCB redeposited on the metal during the developer drying step. It will insure clean metal pads with optimum conductivity and wirebonding performance. The tool can also be used for wafer clean and after metal patterning. Example: 200 mm BCB Etch Process Recipe and Results: Gases: Conditions: Etch Rate: Uniformity: 40 sccm O 2 / 10 sccm SF 6 25°C / 175 W RF / 0. 3 Torr >5000 Å/minute <7% 1 Courtesy Matrix Descum Minimum Configuration - Parallel plate, RF or µwave ~10% acetic acid or 2 -4% H 2 SO 4 dip ( ~ 15 - 60 sec) is needed to remove copper oxides and fluorides after descum. - O 2 line - SF 6 or CF 4 or NF 3 line Etch : 200 - 400 nm Equipment : Matrix, Tegal etc. . . Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 42

INFLUENCE OF PLASMA DESCUM ON BCB SURFACE Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 43

BCB / no plasma (control) Ra (nm) 0. 22 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Rq (nm) 0. 28 44

BCB / 500 W, O 2, 60 sec. Ra (nm) 0. 43 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Rq (nm) 0. 54 45

BCB / 1000 W, O 2, 60 sec. Ra (nm) 1. 74 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Rq (nm) 2. 13 46

BCB / O 2/SF 6 plasma Ra (nm) 0. 79 Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 Rq (nm) 1. 01 47

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Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 49

SUMMARY v CYCLOTENE* HAS EXCELLENT DIELECTRIC PROPERTIES v WATER FREE BCB MOLECULES WITH VERY < 0. 2% LOW WATER PICK-UP OFFER INCREASED RELIABILITY v CYCLOTENE* GIVES EXCELLENT PLANARIZATION v LOW VISCOSITY CYCLOTENE* 402 X GIVES GOOD FILM UNIFORMITY v CYCLOTENE* 402 X IS TRANSPARENT ALLOWING EASY ALIGNMENT Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 50

SUMMARY v BCB IS A WELL UNDERSTOOD PROCESS v PROCESS WINDOW IS WIDE v CONVENTIONAL TRACKS, FEWER HOT PLATES v MULTIPLE DEVELOPMENT STRATEGIES v CURE TIME IS MAXIMUM ONE HOUR AT 250°C, LOW COST OVENS. Albert Achen - Advanced Electronic Materials / Rheinmünster Oct 2001 51