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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

ITRS Conference July 14 - 16, 2003

San Francisco, California

2003 ITRS Yield Enhancement (YE) Update

Fred Lakhani 512/356-7011 fred.lakhani@sematech.org

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Yield Enhancement Presentation Outline

• ITWG Co-chairs and Contributors

• Chapter Outline

• Definition and Scope

• Difficult Challenges

• Technology Requirements and Potential Solutions– Yield Model and Defect Budget (YMDB)– Defect Detection and Characterization (DDC)– Yield Learning (YL)– Wafer Environment Contamination Control (WECC)

• Summary

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

2003 ITRS YE ITWG Co-chairs• Taiwan

– Tings Wang• Promos

Technologies– Len Mei

• Promos Technologies

• United States– Fred Lakhani

• International Sematech

– Christopher Long• IBM

• Europe– Ines Thurner

• Infineon– Dick Verkleij

• fei

• Japan– Masahiko Ikeno

– Renesas – Hiroshi Kitajima

– Selete

• Korea– TBD

Note: Contributions of all TWG members around the world are gratefully acknowledged.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

2003 YE ITWG Contributors• Europe

– Ines Thurner (Infineon)– Dick Verkleij (fei)– Lothar Pfitzner (FhG-IISB)– Andreas Nutsch (FhG-IISB)– Andreas Neuber (M+W Zander)– Hans-Martin Dudenhausen

(isiltec)

• Japan– Masahiko Ikeno (Renesas) – Hiroshi Kitajima (Selete)– Toshihiko Osada (Fujitsu)– –

• Taiwan– Tings Wang (Promos Tech)– Len Mei (Promos Tech)–

• United States– Fred Lakhani (ISMT)– Christopher Long (IBM)– Mike Patterson (Intel)– Kevin Pate (Intel) – Mike Retersdorf (AMD)– Ron Remke (ISMT)– Mike McIntyre (AMD)– Rick Jarvis (AMD)– Ken Tobin (ORNL)– Hank Walker (Texas A&M)– Charles Weber (Portland State Univ.)– Ralph Richardson (Air Products)– Mark Camenzind (Air Liquide) – Joe O’Sullivan (Intel)– John DeGenova (TI) – Jeff Chapman (IBM)– Val Stradzs (Intel)– Keith Kerwin (TI)– James McAndrew (Air Liquide)

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Yield Enhancement Chapter Outline

• Definition and Scope

• Difficult Challenges

• Technology Requirements and Potential Solutions– Yield Model and Defect Budget (YMDB)– Defect Detection and Characterization (DDC)– Yield Learning (YL)– Wafer Environment Contamination Control (WECC)

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Yield Enhancement Definition and Scope

• Definition: – To improve the baseline yield for a given technology

node from R&D yield level to mature yield.– The definition assumes a functional baseline process for

a given process technology and it’s compatibility with the design of the product being fabricated.

– The definition reinforces the chapter focus on the yield ramp portion of the yield learning curve.

• Scope– Limit scope of YE chapter to wafer sort yield.– Fab line yield, assembly/packaging yield and final test

yield are not included in the scope of the YE chapter.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

YE Difficult Challenges

• High-Aspect-Ratio Inspection. – High-speed, cost-effective tools are needed to rapidly detect

defects at 1/2 X ground rule (GR) associated with high-aspect-ratio contacts, vias, and trenches and especially defects near or at the bottoms of these features.

• Non-visual Defect Detection – In-line and end-of-line tools and techniques are needed to

detect non-visual defects.

• Design for Manufacture & Test (DFM & DFT) and Systematic Mechanisms Limited Yield (SMLY)

– IC designs must be optimized for a given process capability and must be testable and diagnosable. Understanding SMLY is mandatory for achieving historic yield ramps in the future.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Void caused by residue left behind after via etch process step

AA BB

CC

DD0

5

10

15

20

180nm

150nm

130nm

100nm

70nm

Aspect Ratios at Future NTRS Nodes

A/B

C/D

Combined

Lower Dielectric

Upper Dielectric

Via Dielectric

Via Etch Barrier

Hard Mask

Canal Etch Barrier

CMP Barrier

Canal

High-Aspect Ratio Inspection (HARI)

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

YE Difficult Challenges (continue)

• Data Management for Rapid Yield Learning. – Automated, intelligent analysis and reduction algorithms that

correlate facility, design, process, test, and work-in-process (WIP) data must be developed to enable the rapid root-cause analysis of yield-limiting conditions.

• Yield Models – Random, systematic, parametric, and memory redundancy

models must be developed and validated to correlate process-induced defects (PID), particle counts per wafer pass (PWP), and in-situ tool/process measurements to yield.

• Correlation of Impurity Level to Yield. – Data, test structures and methods are needed for correlating

fluid/gas contamination types and levels to yield.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

YE Difficult Challenges (continue)

• Line edge roughness, ACLV, subtle process variation. Where does process variation stop and defect start? Need to improve signal to noise to delineate defect from process variation.

• Contamination transferred from wafer edge and backside.

• Unified definition of defects based on yield impact.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Yield Management TodayIncreasing Data Complexity

fabricationprocess

A

fabricationprocess

A

fabricationprocess

B

fabricationprocess

B bin, bit, and parametric electrical

test data

in-lineoptical defect

data

assembly&

final test

assembly&

final test

tool state, ISPM,

moisture,etc.

product data management

system

process data management

system

WIP data management

system

SSA

Databases

optical confocal SEM FIB

ADCSPC

tool state, ISPM,

moisture,etc.

Yie

ld

Man

agem

ent

...

AEA(knowledge discovery)

engineering analysis

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Technology Requirements and Potential Solutions

• Yield Model and Defect Budgets– With systematic mechanisms limited yield (SMLY) dominating

the rate of yield learning, a concerted effort is required to understand, model and eliminate SMLY detractors.

– The impact of line edge roughness (LER) on yield needs to be understood, modeled and controlled to achieve acceptable yields for current and future technology nodes.

– Continuous improvement in tool cleanliness will be required to achieve acceptable yields.

• Defect Detection and Characterization– Cost effective high throughput high aspect ratio inspection

(HARI) tools are needed urgently to achieve acceptable yields for current and future process technology nodes.

– Signal to noise improvements are required for defect metrology tools to detect ever shrinking critical defects of interest.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Technology Requirements and Potential Solutions…continue

• Yield Learning– With increasing process complexity and longer cycle times,

tools and methods are needed to increase the number of yield learning cycles for each technology node.

– With move to smaller features, longer processes, 300mm wafers and new materials (low k, high k, etc.), numerous tools and methods are required to understand all the yield detracting interactions. Use of SOI and SiGe will further challenge yield learning.

• Wafer Environment Contamination Control– Data, test structures and methods are needed to identify and

control yield detracting contaminants in the wafer environment, airborne and process critical materials and ultra pure water.

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DRAFT - NOT FOR PUBLICATION 16 July 2003 – ITRS Public Conference

Summary

• The YE chapter revision for the 2003 ITRS roadmap is well under way. The following regions are taking the lead in revising various sections of the YE chapter:

– Yield Model and Defect Budget Japan– Defect Detection and Characterization Europe– Yield Learning USA– Wafer Environment Contamination Control USA

• Yield critical small defects, high aspect ratio defects, non-visual defects and systematic mechanisms limited yield (SMLY) top the list of challenges for Yield Enhancement.

• The yield enhancement community is constantly challenged to achieve acceptable yield ramp and mature yields due to increasing process complexity and fewer yield learning cycles with each subsequent technology node.