Valery Ray

Particle Beam Systems & Technology, Methuen, USA vray@partbeamsystech.com

High-Throughput Milling of HAR Vias High-Throughput Milling of HAR Vias with Concentrated Gas Deliverywith Concentrated Gas Delivery

PBS&T

FIB User GroupFIB User Group ISTFA 2005ISTFA 2005 San Jose, CA San Jose, CA

04/18/23 FIB User Group, ISTFA 2005 2

Concepts of Concentrated Gas DeliveryConcepts of Concentrated Gas Delivery

Commercial “Shroud” Commercial “Shroud” concentratorconcentrator

““Cupola” Cupola” concentratorconcentrator

04/18/23 FIB User Group, ISTFA 2005 3

Imaging through Shroud Concentrator:Imaging through Shroud Concentrator:FOV 20, 5.8pA Beam, Dielectric SampleFOV 20, 5.8pA Beam, Dielectric Sample

Images taken through Shroud gas concentrator (left) have Images taken through Shroud gas concentrator (left) have lower S/N then images taken with Penta nozzle (right).lower S/N then images taken with Penta nozzle (right).

04/18/23 FIB User Group, ISTFA 2005 4

Main Chamber Vacuum as Function of Gas Main Chamber Vacuum as Function of Gas PressurePressure with “Shroud” Concentrator with “Shroud” Concentrator

0.00E+00

2.00E-06

4.00E-06

6.00E-06

8.00E-06

1.00E-05

1.20E-05

1.40E-05

1.60E-05

1 0.8 0.5

Beehive data Penta Reference, 2 Torr

Factor of ~35 Factor of ~35 pressure reduction pressure reduction in main chamber in main chamber

of FIB systemof FIB system

CCIG, TorrCCIG, Torr

04/18/23 FIB User Group, ISTFA 2005 5

Comparison of 5Comparison of 5µm µm via Milling in SiO2 with via Milling in SiO2 with XeFXeF2,2, Penta (2 Torr) vs. Shroud (0.8 Torr) Penta (2 Torr) vs. Shroud (0.8 Torr)

0

1

2

3

4

5

6

7

8

0.5 0.4 0.3 0.2

0:00

2:24

4:48

7:12

9:36

12:00

14:24

16:48

19:12

21:36

Penta Dose Beehive DosePenta Time Beehive Time

Dose, Dose, nCnC

Time, Time, mm:ssmm:ss

Mill box, Mill box, µmµm

Factor ~ 3.5 throughput Factor ~ 3.5 throughput enhancementenhancement

04/18/23 FIB User Group, ISTFA 2005 6

Endpointing with Gas Concentrator: Endpointing with Gas Concentrator: Secondary Electron SignalSecondary Electron Signal

Secondary electron endpoint of 5Secondary electron endpoint of 5µm deep via made by µm deep via made by 0.3x0.3µm mill box, 5.8 pA beam current, and 0.8 Torr 0.3x0.3µm mill box, 5.8 pA beam current, and 0.8 Torr

XeFXeF22 gas pressure, shroud gas concentrator. gas pressure, shroud gas concentrator.

0V bias0V bias 2V bias2V bias

04/18/23 FIB User Group, ISTFA 2005 7

Endpointing with Gas Concentrator: Endpointing with Gas Concentrator: Sample Absorbed CurrentSample Absorbed Current

Stage current endpoint of 5Stage current endpoint of 5µm deep via µm deep via made by 0.3x0.3µm mill box, 5.8 pA made by 0.3x0.3µm mill box, 5.8 pA

beam, and 0.8 Torr XeFbeam, and 0.8 Torr XeF22 gas pressure. gas pressure.

04/18/23 FIB User Group, ISTFA 2005 8

Indirect Comparison of Via Profile: Indirect Comparison of Via Profile: Penta vs. Shroud (Beehive) FOV 5Penta vs. Shroud (Beehive) FOV 5µmµm

Vias milled by Beehive are expected to have Vias milled by Beehive are expected to have straighter profile then vias milled by Pentastraighter profile then vias milled by Penta

04/18/23 FIB User Group, ISTFA 2005 9

SummarySummary

Concentrated gas delivery is viable for milling of Concentrated gas delivery is viable for milling of multiple access vias in FIB Circuit Edit. multiple access vias in FIB Circuit Edit.

Provides enhanced throughput and reduced Provides enhanced throughput and reduced pressure in main chamber. pressure in main chamber.

Endpoint is reliable with sample absorbed Endpoint is reliable with sample absorbed current and secondary electrons.current and secondary electrons.