《Microelectronics Process》lecture10

3.155/6.,152] Lecture10 Lithography- Part 1 Prof. martin a, schmidt Massachusetts Institute of Technology 10/8/2003

3.155J/6.152J Lecture 10: Lithography – Part 1 Prof. Martin A. Schmidt Massachusetts Institute of Technology 10/8/2003

Outline The lithographic Process a BasIc process Definitions Fundamentals of Exposure Exposure Systems Resists Advanced Lithography Recommended reading Plummer, chapter 5 Other: Campbell, Chapter 7, 8,9 Fall 2003-MA Schmidt 315516.152]- Lecture10-side2

Outline „ The Lithographic Process „ Basic Process „ Definitions „ Fundamentals of Exposure „ Exposure Systems „ Resists „ Advanced Lithography „ Recommended reading „ Plummer, Chapter 5 „ Other: Campbell, Chapter 7,8,9 Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 2

IC Process Circuit design Process simulation An idea- Device Simulation - A file Mask Layout Shop BOXES Design Rules Wafer Wafers Fab Fall 2003-MA Schmidt 3.155] 6.152]-Lecture 10-Slide 3

IC Process Circuit Design Process Simulation Device Simulation Layout BOXES Mask Shop Design Rules Wafers Wafer Fab Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 3 An idea A file

Wafer Fab- Lithography Most Common measure of Complexity of Masks, Minimum Feature(examples) Approximately 50% of the process steps Oxidation H Litho Etch H Oxidation/ Deposition H Litho Etch H Implant Anneal H Litho Etch H Metal Deposition Litho i Etch Sinter Drives infrastructure Cleanliness Vibration Temperature and humidity Fall 2003-MA Schmidt 3.155] 6.152]-Lecture 10-Slide 4

Wafer Fab - Lithography „ Most Common Measure of Complexity „ # of Masks, Minimum Feature (examples) „ Approximately 50% of the Process Steps Litho Etch Oxidation/Deposition Litho Etch Implant Anneal Litho Etch Metal Deposition Litho Etch Sinter Oxidation „ Drives Infrastructure „ Cleanliness „ Vibration „ Temperature and Humidity Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 4

Semiconductor Roadmap Year of first DRAM Shipment 1997 1999 2003 2006 2009 2012 DRAM Bits/ Chip 256M1G 4G 64G256G Minimum Feature Size nm Isolated Lines(MPU 200 140 100 Dense Lines (DRAM) 250 130 100 70 Contacts 200 140 110 Gate CD Control 3c(nm) 10 Alignment(mean 3o)(nm) 65 Depth of Focus(um) 0.8 0.7 0.6 0.5 0.5 0.5 Defect Density (per layer/m?) 100 80 60 40 Defect Size (nm) @80@60@40⊙30@20⊙15 DRAM Chip Size(mm?) 280 560 790 11201580 MPU Chip Size(mm2) 300 360 430 520 620 750 Field Size(mm) 22x2225x3225x3625x4025x4425x52 Exposure Technology 248mm248nm248nm193mm193mm? DUV DUV DUVDUV 193nm UV Minimum Mask Count 22/2424 24/26262828 Fall 2003-MA Schmidt 3. 155]6. 152]-Lecture 10-Slide 5

Semiconductor Roadmap Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 5

Pattern Transfer Steps Coat with photoresist pose Mask ++t Develop Etch Strip resist Wet etch Fall 2003-MA Schmidt 3.155]6.152]-Lecture 10-Slide 6

Pattern Transfer Steps Mask Coat with photoresist Develop Strip resist Expose Etch* *Wet etch Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 6

Definitions Metrics Resolution Throughtput Registration(Alignment) Exposure Systems-UV Projection -Fraunhofer Proximity-Fresnel Contact -Fresnel Advanced DUV, E-Beam, X-Ray, Nano-imprint Resists a Positive/Negative Contrast CMTE Fall 2003-MA Schmidt 3. 155] 6. 152]-Lecture 10-Slide 7

Definitions „ Metrics „ Resolution „ Throughtput „ Registration (Alignment) „ Exposure Systems - UV „ Projection - Fraunhofer „ Proximity - Fresnel „ Contact - Fresnel „ Advanced „ DUV, E-Beam, X-Ray, Nano-imprint „ Resists „ Positive/Negative „ Contrast „ CMTF Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 7

Lithography Systems Proximity Contact rojection Mask Wafer Fall 2003-MA Schmidt 3.155]6.152]-Lecture 10-Slide 8

Lithography Systems Proximity Contact Projection Mask Wafer Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 8

Contact/ Proximity Printing Aperture Resist Wafer Incident Plane Wave Proximity Projection Contact Light Intensity at Resist Surface Separation Depends on Type of System Fall 2003-MA Schmidt 3.155]6.152]-Lecture 10-Slide 9

Contact/Proximity Printing Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 9

Contact/ Proximity Printing Mask Incident Plane Wave Aperture Resist Wafer Applies when x <g< w2/it inestyrRrs Minimum resolvable feature =(g)1/2 Fall 2003-MA Schmidt 315516.152]- Lecture10-side9

Contact/Proximity Printing Fall 2003 – M.A. Schmidt 3.155J/6.152J – Lecture 10 – Slide 9 Applies when O < g < W 2 / O Minimum resolvable feature = ( Og)1/2