product support lds detail test plan

PRODUCT SUPPORT STRATEGY

Engineer: J.KronePhysicist:B.McDougall

ALD LDS BETA II TEST PLAN Chemistry: Si3N4 by SiCl6-N2H4

Table of ContentsList of Figures.............................................................................................2List of Tables..............................................................................................2Test Plan Instructions [See 022512-95].........................................................2Product Support Objective..........................................................................2

Commission Beta II for LDS.......................................................................................................2

Hardware Setup and Hardware Definition..........................................3LDS plumbing upgrade and seal modification for Tris [tertpentoxy] Silanol....................3

Hardware installation review................................................................4LDS plumbing lines cycle purge and functionality review:........................................................4Simulation of the ALD of Tris [Tert-pentoxy] Silanol with dummy gases.................................6Install live precursors: Tris [Tert-pentoxy] Silanol....................................................................7ALD of Si02 with Tris [Tert-pentoxy] Silanol..........................................................................10Determine process endpoints.....................................................................................................12

Materials..................................................................................................13Results See Process Specification;..............................................................14

Particles:...................................................................................................................................14Metal Contamination:.............................................................................................................14Film Stress:...............................................................................................................................14In-film/On-film Particles:.......................................................................................................14Optical Properties:...................................................................................................................14Electrical Tests:........................................................................................................................14Surface Morphology:...............................................................................................................14Chemical Structure:................................................................................................................14Film Profile:.............................................................................................................................14Step Coverage:.........................................................................................................................14

Conclusions:...........................................................................................15

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Form has been reviewed for completeness. Initials: __________ Date:__________

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List of FiguresFigure 1: LDS System Schematic [Ref Torrex drawing 022362-01].............................................8Figure 2 Indexer Seal Retrofit........................................................................................................8Figure 3 Plan View LDS Components............................................................................................9

List of TablesTable 1: Process parameters for simulated ALD Recipe ALD_SIM_a..........................................6Table 2: Process parameters for ALD Recipe ALD_a.................................................................11Table 3: Properties of LTSiN Films from BTBAS-NH3 and from DCS-NH3 Chemistries.......12Table 4: Measurements from Nanometrics 8300 XSE.................................................................14

Test Plan Instructions [See 022512-95]Provide strategy to test installation of the LDS system. Include the types and sequence of experiments, the DOE design, the DOE variables, optimization strategy, metrology strategy and any other information that is pertinent to defining the development strategy. Address:

How to meet process requirements? How will we confirm that the LDS meets minimum flows specified? What chamber pressure characterization will be useful? What is the process latitude? How does the process integrate with the software provided?

Product Support ObjectiveThe process objective defined by this test plan is for the short-term and is for the atomic layer deposition (ALD) of SiO2 with Tris [Tert-Pentoxy] Silanol, Tri-t-butoxysilanol, and Hexaethylamidosilane [HEADS] in that order over a six week span. Pending process results, a subsequent test plan that defines a DOE for a Flexstar tool is expected.

Commission Beta II for LDS Replace existing indexer seal to reduce process chamber volume. Simulation of the ALD for Tri-[Tert-Pentoxy] Silanol with IPA Install Tri-[Tert-Pentoxy] Silanol and run test wafers.

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Hardware Setup and Hardware DefinitionLDS plumbing upgrade and seal modification for Tris [tertpentoxy] Silanol.See Kit, Beta 2, LDS Upgrade [022512-01]

Pertinent Issues: -System is able to control the LFM [MFC-20] at 10% of F.S., which is IPA flow of <5.18 g/min.-System is also able to control LFM [MFC-20] at 5% of F.S., which is IPA flow of <2.8 g/min. - System is also able to control MFC-22 at =< 3.0 % F.S. or 70 SCCM of carrier gas for the vaporization.- Vapor delivery heated line should be maintained at higher than 40 C less than 65 C to prevent re-condensation under all events, except IPA tests where temp is to be 50 C.

- Measure injector pressure with 70-300 SCCM N2 carrier gas flowing through open CEM.- Bake out gas lines after IPA test at 120C for 12 hours.

-The temperature set point of the vaporizer is 60 C for IPA and will be higher for actual usage.- N2 Carrier gas to be high purity.- IPA to be 99.99% pure.

-General Procedure for one dose step. 1. Introduce carrier gas to vent line. 2. Supply the setting point to the LFM. 3. Open valve to injector line for deposition. (x seconds) set LFM to zero. 4. Switch the vapor line back to vent line. 5. Keep flowing carrier gas. 6. Stop the carrier gas, but keep pumping out to vent line.

Action Items:1) Record data and determine best settings for various precursors.2) Revise control code for valve timing as determined during set up.

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Hardware installation review

LDS plumbing lines cycle purge:

Referring to Torrex Drawing 022362-90 Sheet1/1. Review ‘state’ diagram for accuracy. This step insures no moisture is introduced into LDS system, similar procedures are acceptable, but need to be documented prior to use. After initial installation of the ALD LDS System, with the exception of heated segments, all components are assumed to be at RT following an extended bake-out (24 hours) of the process chamber. No measurable leaks and an acceptable ROR has been recorded with the new indexer seal in place. The reactor and boat have been coated with best-known-method [BKM] at 630 C.

Inside the Chemical Cabinet

1. Verify that MV-23, MV-24, MV-25, MV-26, and PV-131 are closed. Check He pressure regulator in gas box for setting of 8-10 PSI maximum. [Record pressure on gauge]

2. Install the IPA canister [For initial calibration of system] in liquid delivery mode [Dip tube on right] inside the LDS {BLUE} cabinet.

a. Place precursor canister on scale assembly.b. Connect He push-gas flexible line to MV-21, which remains closed.c. Connect liquid draw flexible line to MV-22, which remains closed.

i. Note any apparent significant change in weight of bubbler.d. Check He pressure and set regulator to <10 PSI as read on the gauge. Insure ‘Gas

Vac Pump’ foreline is at <1 Torr, Open MV-24. Slowly open MV-25 to evacuate initial air/He mixture from trapped volume of canister spools that are defined by MV-21, MV-22, MV-23, MV-26, & PV-131, allow several seconds for pump down of this volume. Close MV-25 and open MV-26 to fill with He. Record He pressure at gauge near regulator.

e. Close MV-25 and MV-23 slowly open MV-26 to evacuate He from spools volume.

i. Close MV-24, MV-23, MV-25, and MV-26 with push gas spool volume filled with the a cycle’s He fill. Verify MV-27 is closed and open MV-23 and PV-131 from LDS screen [manual mode] in preparation for next step. [Note: this step will fill line up to MV-27 with positive He pressure.]

ii. Now cycle purge up to MV-27. Close MV- 23, open MV-24 and MV-25 allow several seconds to purge He, close MV-25 and MV-24 then open MV-23 fill with He repeat cycle 5 times.

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iii. Leave this last gas line section in vacuum not He fill.

At the LDS on the Process chamber3. Verify that PV-106, 105, 112, 108, 109, 111, and MFC-22 are closed in preparation of

cycle purging the LDS vaporizer section to remove vestiges of air. CEM LFM-20 is off but CEM-V1 is open [LFM-20 PIN 5 TO 13 VDC].

a) N2 Purge of valve block; set point flow of MFC-21 to .8-1.2 SLM open PV-235 and set MFC-22 to 1.5 SLM. Open PV-105, PV-106 and open PV-109 so that N2 is flowing to pump stack wait several seconds and close PV-105, repeat this step 5 times to purge the volume inside the three way valve block of PV-105 and PV-106.

b) N2 Purge of liquid delivery lines; open PV-105, PV-106, , [CEM V-1 is normally open when no power is supplied to CEM LFM], open PV-108 so that is N2 flowing to pump stack through PV-109 with MFC-20 set at .8-1.2 SLM wait several seconds and close PV-105 for three seconds and open again, repeat this step 5 times to purge the volume inside the liquid delivery components branch.

c) [Verify that PV-106, 105, 112, 108, 109, 111, MFC-22 are closed in preparation of cycle purging the LDS carrier vaporizer section.] Set N2 carrier MFC-21 to flow 500 SCCM [10% flow]. Open MFC-22 to flow 300 SCCM N2 carrier gas. Close CEM-V1 [MFC-20 PIN 5 TO 0 VDC]. Open PV-108 and PV-109 to flow N2 through the carrier piping out to the pump stack for about 10 seconds. Shut flow from MFC-22 and let piping pump for 10 seconds. Repeat this series of purge /pump steps for 5 iterations.

d) Verify that PV-128, 126, 127, 129, 130 are closed and PV-66-B is open. Open MFC-22, PV-112 and close PV-109 and PV-108. Allow for N2 carrier gas flow through the chamber, let it stabilize, shut the throttle valve and note the pressure change in the injector during the next 60 seconds. Turn off MFC-22, open the throttle valve and let the chamber stabilize to base pressure. Repeat this step with MFC-22 set at 70 SCCM and note the pressure change in the injector.

e) Shut all LDS valves and set LFM [MFC-22] to zero flow. f) Close MV-26 and open MV-23, MV-25 and MV-24 to evacuate He from spools

volume for two minutes, shut MV-23, MV-25 and MV-24.g) Open PV-131, MV-27, PV-105, and PV-109 and pump for @ two minutes. Shut

PV-131, PV-105, and PV-109 in that order. This will provide a low pressure in the liquid delivery line up to CEM-V1 to reduce entrapment.

h) Insure CEM [MFC-20] is set to zero flow. Check that the secondary pressure regulator [0-20 PSI] is set that the gauge shows .5 PSI. Open MV-26 then MV-21 L/T, then open MV-22 L/T. Open PV-131 and IPA will flow into piping up to

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CEM-V1. System is ready to start IPA process mode review. [See following data collection steps]

Simulation of the ALD of Tris [Tert-pentoxy] Silanol with IPAAlthough valve sequencing is assumed to be correct in the implemented software and by design intent, simulation of ALD SiO2 with IPA is scheduled to confirm valve sequencing with the DAC and to confirm adequate software logging of process parameters. LDS heater control will be through the Eurotherm controller provided for the additional heaters used by the LDS and will be independent of the interlocks built into the software. The LDS canister filled with IPA has been placed in the ‘Chemical Cabinet’ see that previous purge steps have been accomplished.

a. Confirm that valve sequencing recorded by DAC is consistent with published valve sequencing ‘state’ diagram.

i. Note: DAC may not have sufficient number of ports to monitor all valves, so repeat simulated process until all valve sequencing confirmed.

b. Confirm process log file provides adequate record of all process parameters.

Table 1: Process parameters for simulated ALD Recipe ALD_SIM_A.

Step 0 Step 1 Step 2

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Step 0 Step 1 Step 2

Install live precursors: Tris [Tert-pentoxy] Silanol [TPS].Installation occurs with the observation or approval of a Hazard Material Team member referring to Torrex Drawing 022362-90 Sheet1/1.

Inside the Chemical CabinetInstall the TPS canister, in liquid delivery mode [dip tube on right] inside the LDS {BLUE} cabinet.Do not open MV-21 and MV-22 until system is in process mode.

a. Place precursor canister on scale assembly and record initial weight.b. Connect He push-gas flexible line to MV-21, which remains closed.c. Connect liquid draw flexible line to MV-22, which remains closed.

i. Note any apparent significant change in weight of bubbler.d. Check He pressure and set regulator to <1.2 PSI as read on the gauge. Insure ‘Gas

Vac Pump’ foreline is at <1 Torr, Open MV-24. Slowly open MV-25 to evacuate initial air/He mixture from trapped volume of canister spools that are defined by MV-21, MV-22, MV-23, MV-26, & PV-131, allow several seconds for pump down of this volume. Close MV-25 and open MV-26 to fill with He.

e. Close MV-24 and MV-23 then open MV-26 to fill with He in the push gas inlet alone, for several seconds.

f. Close MV-26 and open MV-25 to evacuate He from spools volume.i. Pump-purge, i.e. repeat Steps D-F, five times.

ii. Close MV-24, MV-23, MV-25, and MV-26 with push gas spool volume filled with the fifth cycle’s He fill. Open PV-131, MV-27, PV-105, and PV-109 and pump for @ two minutes. Shut PV-131, PV-105, and PV-109 in that order. This will provide a low pressure in the liquid delivery line up to CEM-V1 to reduce entrapment.

g. Insure CEM [MFC-20] is set to zero flow. Open MV-26 then MV-21 L/T, then open MV-22 L/T. Open PV-131 and TPS will flow into piping up to CEM-V1. System is ready to start process mode review.

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..\..\..\..\..\temp\0981\022362-91.dwg

Figure 1: LDS System Schematic [Ref Torrex drawing 022362-01]

..\INDEXER SEAL\022355-01.doc

022355-00 A

KIT,INSTALL,SEAL ROT,BETA,UPGRADE

JKRONE 9/22/03

JKRONE 9/22/03022355-01 1:1 1/1

.8

.3

.13

.5°

A 0975 JK 9/22/03 JK 9/22/03

RECORDED ON DRAWING, AND SHIPPED WITH PART.

6. CLEAN AND PACKAGE PER TORREX PROCEDURE, ITEM 999

4. DIMENSIONS APPLY TO FINISHED PRODUCT

5. DIMENSIONS ENCLOSED BY AN OVAL XXX TO BE MEASURED,

2. FINISH: N/A

1. MATERIAL: SEE BOM

NOTES:

3. UNLESS OTHERWISE NOTED, ALL MACHINED SURFACES TO BE

OR BETTER, BREAK ALL CORNERS AND SHARP EDGES.1.60 [63]

Figure 2 Indexer Seal Retrofit

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Figure 3 Plan View LDS Components

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Process Mode; ALD of Si02 with Tris [Tert-pentoxy] Silanol.This area is subject to process engineering revision prior to release of this test plan, but not inclusive thereof. This section has been included to set control temperature points for the chamber walls due the new precursors. The estimated deposition rates due to limits of the liquid delivery system used for this initial test, based on best methods for estimating TPS behavior.The target thickness for the ALD of SiO2 is z=30 Å. To ensure surface saturation for any exposure, each ALD half-cycle is repeated twice for the initial deposition tests. This means that each ALD cycle is increased from twelve steps to twenty-four steps. Each ALD step also is increased by a factor of two in estimated duration. The deposition rate is about 1.1 Å per ALD cycle. Table 2 shows the parameters for ALD Recipe ALD_a. The criteria that must be met before exercising live ALD are:

Installation of live precursors. Successful simulation of the ALD of SiN. Completion of ten automated wafer cycles with the simulated ALD of SiN.

o Duration of the simulated process steps may be the minimum duration allowed by software.

After the criteria are satisfied, then exercise ALD Recipe ALD_a with ten reclaimed grade bare Si wafers of diameter 200 mm. Repeat until ALD SiN is confirmed by observations defined in Metrology Strategy.

1. Characterize flow characteristics of all relevant MFCs at room temperature (RT) with N2.o Acquisition of flow characteristics from MFCs required for ALD may be deferred

until after CVD poly-Si is confirmed.2. After proper functioning of MFCs confirmed, heat reactor to temperature T=630 C.3. Fix the wall temperature of the reactor to > 70 & < 100 C.4. Run particle and metal contamination wafers.

o Six particle wafers are required, and all particle wafers start from LP 2 except the control wafer.

One particle wafer (control) remains in the cassette. One particle wafer remains in LP 2. One particle wafer moves to LP 1. One particle wafer moves to TM. One particle wafer moves to PM. One particle wafer moves to the Cooling chamber.

o Three metal contamination wafers are required, and all metal contamination wafers start from LP 2 except the control wafer.

One metal contamination wafer (control) remains in the cassette. One metal contamination wafer is moved to slot 10. One metal contamination wafer is moved to slot 5.

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The metal contamination wafers are run with simulated process for the CVD of 1500 Å of poly-Si at T=630 C.

The simulated process for the ALD of C15H34O4Si on metal contamination wafers will be different, but the standard ALD process will be used.

5. Coat reactor and boat with 1 m of poly-Si with the most recent best-known-method (BKM) process at T=630 C.

6. Deposit poly-Si with thickness z=1500 Å on 200 mm oxide wafers with the most recent BKM process at T=630 C.

o The load zone is defined to be ten susceptors center-aligned with the shields.o Reclaim grade wafers are adequate.

7. For a ten-wafer load zone center-aligned with the shields, document the standard deviation for WiW z, WtW z, WtW T, RtR z, and RtR T from five runs.

o Measure z with the Prometrix.Run particle and metal contamination wafers as described in Item 3.

Table 2: Process parameters for ALD Recipe ALD_a

Step 0 Step 1 Step 2TPS (sccm) 0.00N2 Purge (sccm) 0.00LDS Carrier (sccm)

0.00

LFC 2.2gm/min) 0.00LDS (Idle, fill, dose, or pump)Loop 0Pressure Mode (Set, open, or close)Pressure (mTorr) 0.00Time (sec) 0

A heat re-circulator is used to fix the wall temperature of the reactor, and the heat re-circulator is set to100C. Heating the walls of the reactor prevents condensation of precursors and reduces the total pressure during the second half reaction.. Since the reactor pressure at equilibrium is always less than 18 Torr, a wall temperature greater than 315 K (60C) is adequate. A setting of 100C provides sufficient margin to ensure an internal wall temperature greater than 70 C given the thermal mass of the reactor, the distribution of heater fluid in the reactor walls, and air conditioning.

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Determine process endpoints.After the successful ALD of SiO2, then process endpoints must be determined before specifying a DOE to optimize film properties. For reference, Table 3 lists SiN film properties for furnace DCS-NH3 and for BTBAS-NH3

processes. For the tunnel barrier application, the Cl concentration must be minimal, but an upper limit is not specified at this time. A typical Cl concentration for DCS-NH 3 films has not been extracted from the literature as of this writing.

Table 3: Properties of LTSiN Films from BTBAS-NH3 and from DCS-NH3 Chemistries

Parameter BTBAS-NH3 DCS-NH3 Furnace Control

Wafer temperature (oC): 630 750Deposition rate (Å/min): 20 (P=4 Torr) > 10WiW, WtW, RtR thickness uniformity (%, 1):

< 1 < 1

BacksideNon-uniformity (%, 1):

< 30 < 1

Stress (MPa, Tensile): 1250 1100 - 1300Step coverage (4:1 AR) (%): 90%-95% 95 % - 100 %Composition (Si/N) (Atomic %): 0.77 0.75Refractive index: 1.96 2.0Microstructure: Amorphous AmorphousRoughness (Å): 2.4 <3Impurities:[H](Atomic %)[C] (Atomic %)[O] (Atomic %)Heavy metal (frontside, cm-2)Heavy metal (backside, cm-2)

10±23±20.4±2< 1010

< 1011

6±2detectable limitdetectable limit

∆ (Si-H) @ 850 oC (%): < 10

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Parameter BTBAS-NH3 DCS-NH3 Furnace Control

Wet-etch rate:Hot Phosphoric Acid (Å/min)10% HF (Å/min)

0.811.12

1.01.0

Electric Field@ 10-6A/cm2 (MV/cm)

4.75 (Thickness=500Å)5.4 (Thickness=1000Å)

4.75 (Thickness=500Å)

Dielectric constant: 6.6 6.7Adhesion (SiN/Si, SiN/Oxide) Pass PassProcess particle adders (0.16 μm) 4 < 40

Measure the process endpoints for reactor pressure, reactor temperature, step duration, repeat number for each half of an ALD cycle, temperature for each zone of the LDS, and wall temperature of the reactor. Basic characteristics for the ALD of SiO2 with Tris [Tert-pentoxy] Silanol are:

At low temperatures, the dependence of film thickness on T is Arrhenius. At mid temperatures, the film thickness is independent of T. At high temperatures, the film thickness decreases with T. For step duration, pressure, and repeating of ALD half-cycles, the film thickness depends

linearly on the number of ALD cycles completed. For adequate zone temperatures of the LDS, the film thickness depends linearly on the

number of ALD cycles completed.o Condensation of precursors in the lines of the LDS must be negligible.

At the optimal wall temperature of the reactor, localized reactions must be minimal. Caution: electrical properties of an atomic layer deposited film can be impacted by exposure despite satisfying the basic characteristics of an ALD process.

Materials..\BOM\022512-01.xlsTorrex Confidential

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..\PRECURSORS\Matrix LDS Precursors.doc

Results See Process Specification;Particles:

Results pending deposition tests.

Metal Contamination:Results pending deposition tests.

Film Stress:The FSM likely cannot measure film stress for ALD SiO2 because the reflected laser signal will be too small. Film thickness greater than 1.2 kÅ is required for adequate signal, but depositions are less than 100 Å. Nanoindentation is likely the best technique to quantify film stress.

In-film/On-film Particles:Results pending deposition tests.

Optical Properties:Optical properties of the films are to be determined by VASE on the Nanometrics 8300 XSE. Table 3 will show results by Run ID.

Table 4: Measurements from Nanometrics 8300 XSE

Run ID Rate [Å/min] WiW 1 WtW 1 Refractive Index

Electrical Tests:Results from CV and IV are pending.

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Surface Morphology:Results from AFM are pending.

Chemical Structure:Results from , XPS, FTIR and etch rate tests are pending.

Film Profile:Results from RBS and from SIMS are pending.

Step Coverage:Results from electron microscopy are pending.

Conclusions:Comments are pending results.

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product support lds detail test plan

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process parameters

simulated ald recipe

process mode ald of

process specification

process requirements

process endpoints