Integrated Dual Damascene Etching for · Etch Products Business Group Summary! Requirement for integrated dual damascene etch processes has been observed. It requires new etch tool

Etch Products Business Group

Integrated Dual Damascene Etching for 65nm Technology and Beyond

Yan Ye, Ph.D.Dielectric Etch Technology DevelopmentApplied Materials,PEUG Meeting, Aril 13, 2004


Content

! Trends in dual damascene development! Integrated dual damascene etch process! Challenges for integrated etch process. ! Feasibility of integrated dual damascene etch process.

Integrated etch process is one of major challenges for dual damascene etch applications of 65nm technology and Beyond


Low-K Dual Damascene Trends Observed

I-line

248nm Litho

k-va

lue

Technology Node250nm 180nm 130nm 90nm 65 nm

1.5

2.0

2.5

3.0

3.5 FSG/SiN

OSG-I/SiC-I

193nm Litho

157nm Litho?

OSG-II/SiC-II

Porous OSG/SIC-II

45 nm

USG4.0

Trench FirstVia first

Via FirstTrench first

New DD structure?Via First

Both low-k material and lithography are the driving forces for new dual damascene schemes


BARC Etchback Approach

Pre M2 etch Ash+ Barrier open


Pre BARC etch M2 etch 2

Dual Damascene with Full-Filled BARC


Dual Damascene with Bi-layer ResistPre Mask etch Trench etch

Ash Barrier open


Why Integrated Etch Process is Needed


Low-K Dual Damascene Process

BD Via EtchM1 Trench Etch

BD DD 2nd Trench etch and Blok open


All-in-One

Wet Dip

Dip

Wet Dip

Dip

TraditionalEtch Scheme

Lithography PR StripTrench Etch Barrier Open Cu Deposition

4 tools / ~4.5 hrs cycle time4 tools / ~4.5 hrs cycle time

Wet Dip

Enabler: Cycle Time Advantage

1 tool/~30min1 tool/~30min

Representative Fab Layout


Challenges Faced For Integrated Etch Process


Etch of Diverse Low-κ Materials and Integration Schemes is Required

Large Operation Window is Required for an All-in-One Dual Damascene Process

BD Via Etch

BD Trench Etch

BLOκκκκ Open

PR Strip


500O2/10-900mT/100-4500Wb/0-2000Ws

Oxygen Emission intensity (774nm)

Vrf measured fromCathode (Volts)

Time (s)

-2000

-1000

0

1000

2000

3000

4000

0 50 100 150 200 250

Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8

Fast transition between steps is Required for an All-in-One Dual Damascene Process


All-in-1 Process Requires Tunability for Both Charged Species and Neutral Species Distribution in Each Step

Independent control of both charged and neutral species distribution is necessary to achieve complete tunability of etch rate uniformity and profile/CD uniformity

Independent control of both charged and neutral species distribution is necessary to achieve complete tunability of etch rate uniformity and profile/CD uniformity

-40-35-30-25-20-15-10

-50

0.50 1.00 1.50 2.00 2.50

∆CD

[nm

]

CtrEdge

Edge∆∆∆∆CD: 32 nm

Center

Center Edge∆∆∆∆CD: 3 nm

Effect of Neutral Species Distribution Tuning

3000

6000Across-Wafer Etch

Rate Profile

ER

(A/m

in)

CTR EDGE CTR EDGE CTR EDGE

Center-Fast Edge- Fast~1.% unif.

Effect of Charged Species Distribution Tuning


TOP CTR BTM

Main etch

Identical process performance is required Identical process performance is required

CTR TOP

CTR TOP

TOPCTR

Over etch

2-in-1PR Strip in a clean chamber

All-in-1Etch, PR Strip, chamber clean

Integrated Etch Process Requires Process Transferable: All-in-1 via etch comparison with 2-in-1 etch


Feasibility of Integrated Etch Process


Integrated BD Dual Damascene M2 Trench Etch

Etch Insitu Ash BLoK Open

All-in-1 BD Dual Damascene Trench etch is DemonstratedAll-in-1 BD Dual Damascene Trench etch is Demonstrated


All-in-1 Low-K Film Integrity Repeatability Test:BD I M2 etch profile after ash & HF dip

Ash

HF Dip

Wafer #1 Wafer #200 Wafer #1000

No Low-k film integrity change in 1000 wafer burn-in


00 500500 10001000 15001500 20002000 Post PMPost PM

2000 Wafer Burn-in Result for All-in-1 BD M2 Trench:Process and Particle Performance

Process and particle performance are stable through 2000 wafers burn-in.

Cycle Wafer Count 0 500 1000 1500 2000 Post PM

Fence (A) 0 0 0 0 0 0U-loading (%) -2.6 -1.6 -2.9 0.3 -0.6 -2.1

ED (A) 3180 3120 3180 3080 3100 3100NonU(%) 3.3 1.8 2.9 2.4 1.1 2.4

RF-on Particle Chart

0

5

10

15

20

0 25 100

200

300

400

500

750

1000

1250

1500

1750

2000 PM

2050

Wafer count #

Part

icle

Add

er

0

5

10

15

20

>.12um >10um >.12um >10um

The average particle adders are 3.9 and 2.9 for

>.12um and >0.20um


3 Level Metal Copper BD Interconnect Built Through Integrated Etch process

3 level Copper Interconnect with 95-99% yield 10 Million via chain as well as stacked 1 Million Via Chain

Via1

Stacked Via

3 level Copper Interconnect

M3V2M2V1M1

Via 2

Via resistance (ΩΩΩΩ)


All-in-1 CDO (k~2.3) Trench Etch with 193nm PR

DICD 109nm1σ=2.8nm

FICD 93nm1σ=2.8nm

Ctr

Edge


Integrated Porous OSG (ELK) Etch

M 1(Cu)

Oxide

Porous Silica 4.0K

Porous Silica 4.0KSiC 2.0KSiO 0.5K

SiC 1.0K

SiC 1.0K

Demonstrated all-in-1 capabilityDemonstrated all-in-1 capability

All-in-1 Result


Summary

! Requirement for integrated dual damascene etch processes has been observed. It requires new etch tool with large process window, better tunability for both charge species and neutral species in each step, smooth step transition, effective clean without low-k film damage, and so on. Feasibility to achieved required etch performance for several integrated dual damascene scheme has been demonstrated.


Documents

Integrated Dual Damascene Etching for · Etch Products Business Group Summary! Requirement for integrated dual damascene etch processes has been observed. It requires new etch tool