Results Overview Wafer Edge Film Removal using Laser

Transcription

1 Results Overview Wafer Edge Film Removal using Laser

2 LEC- 300: Laser Edge Cleaning Process Apex Beam Top Beam Exhaust Flow Top Beam Scanning Top & Top Bevel Apex Beam Scanning Top Bevel, Apex, & Bo+om Bevel Bo+om Beam Bo+om Beam Scanning Bo+om & Bo+om Bevel Note: Top, Bo+om, and Apex beams are directed sequen9ally to the wafer s edges in a single opera9on. 2

3 Laser Cleaning Mechanisms Nanosecond laser pulses provide localized transient hea9ng; Depending on the fluence, reflec9vity, and the physical proper9es of the film, one or more of the following occurs: Gas Reac9on Zone Case 1) Substrate evapora9on at the interface will remove most films Case 2) Differen9al thermal expansion causes materials to break away from the surface Case 3) Photoabla9on of thin organic films The material removed from the surface is super- heated and reacts in a combus9on process with the ambient air forming the gas reac9on zone. The combus9on by- products may be gasses, liquids, or solids. They are carried away from the wafer by high- velocity exhaust. 3

4 LEC- 300: Laser Edge Cleaning TOP Laser Clean 10 mm 0.5mm and below APEX Laser Clean BOTTOM Laser Clean 10 mm 0.5mm and below 4

5 50µ Film Removal Accuracy Edge Exclusion Accuracy Specifica9on: ± 0.05mm Edge Exclusion Experiment Target: 1.00 ± 0.05mm Edge Exclusion Experiment Result: ± 0.034mm Applica9on 1 Reading # Edge Width W (mm) Average 0.98 Standard Dev Applica9on 2 Reading # Edge Width W (mm) Average 0.98 Standard Dev Applica9on 3 Reading # Edge Width W (mm) Average 1.02 Standard Dev

6 Less than 200 nm acsve area loss Edge Exclusion Accuracy SpecificaSon: ± 0.05mm Top Edge Exclusion Experiment Target: 0.20 ± 0.05mm Top Edge Exclusion Experiment Result: ± 0.041mm ApplicaSon 1 Reading # Top Edge Width (mm) Average Standard Dev um 0.18mm Top Edge of Wafer 0.45 mm Physical Edge of Wafer Cleaned Area 6

7 Standard Process Time (Sec)* Many films removed with one tool Unprocessed Processed 5 0 Single- layer Resist Post- etch Polymer Tri- layer Resist Si- ARC on Hard Mask (SOC) NiPt TiN W Other applica9ons include: SiN; SiO 2 ; Polysilicon; Black Silicon; CMP Residues on SiO 2 ; PVD Cu, Ta, Ru Stack on SiO 2 *Standard Process: Removal of 0.5mm on Top of wafer plus Apex (Bo+om process requires added 9me) 7

8 15nm TiN 60nm SiO2 Si Substrate TiN BKM 2 EDS Results Element Control Processed N K O K Si K Ti K Totals % % 0.54% Ti and 0% N Left New beam result is 0.50% Ti Profilometry Results Sample Control Processed R PV (µm) R RMS (µm) µm R RMS New beam result is 0.043µm R RMS 8

9 NiPt LEC-300 NiPt Stack 5nm TiN 7nm NiPt Si Substrate 50X Photomicrograph EDS Results (Atomic %) Element Control Processed Ti K 0.69% 0.00% N K 0.00% 0.00% Ni K 3.05% 0.00% Pt K 0.40% 0.00% O K 0.00% 16.64% Si K 95.86% 82.36% Totals % % 0% Ti/N/Ni/Pt Left Averaged Profilometry Results 50μm Sample Control Processed R RMS (µm) R PV (µm)

10 W BKM W Stack 50nm W 5nm WN 50nm Poly 50nm TOx Si Substrate 50X Photomicrograph of Processed Area EDS Results Element Control Processed W M 29.03% 0.00% O K 9.07% 28.09% Si K 61.90% 71.91% Totals % % Profilometry Results Sample Control Processed R RMS (µm) R PV (µm) μm

11 Removal of Post- Etch Polymer (PEP) from Si a]er Plasma Etching Before Laser Cleaning After Laser Cleaning Si Substrate CF x from CF 4 Etch SiO from O 2 Etch CF x from CF 4 Etch 0.14µm PEP Bo+om 0.02µm Residue Initial PEP Thickness Distribution 0.45µm PEP Bevel Residue Below Detection Limit Bo^om Bevel Apex 0.21µm PEP Apex 0.045µm Residue SEM Image Locations Sample mounted upside down The stack is removed at a rate of ~15 sec/mm of edge width. 11

12 LEC- 300: Throughput & Cost of Ownership ApplicaSon Top Process Time (sec) Apex Process Time (sec) Tool Overhead (sec) Wafers Per Hour Running Cost per Wafer* Total Cost per Wafer** Single- layer Resist $0.070 $0.34 Post- etch Polymer $0.072 $0.35 Tri- layer Resist $0.074 $0.36 SOC Hard Mask $0.080 $0.39 Nickel PlaSnum $0.082 $0.40 Titanium Nitride $0.092 $0.44 Tungsten $0.115 $0.54 Note: Wet edge clean and Plasma edge etch Total CoO typically in excess of $2.00/wafer Assump9ons: Single robot, single FOUP, one laser, 300mm wafers Process 9mes are based on removal of 0.5mm on Top of wafer plus Apex (Bo+om process requires added 9me) Tool overhead includes all moving components (robot, pre- aligner, spinner, exhaust, mirrors) plus wafer centering * Running cost assumes 90% u9liza9on in automated factory and includes power, maintenance, gases, and personnel ** Total cost adds equipment cost ($1,000,000 nominal purchase price, 5- year deprecia9on) 12