MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS.pdf - 第612页

MIL-STD-883F METHOD 5004.11 18 June 2004 22 APPENDIX A ATTACHMENT 2 EXAMPLE OF DEFECT DETECTION FOR KEY PROCESS STEPS: PROCESS STEP PRODUCT MONITOR EQUIPMENT MONITOR RELIABI LITY MONITOR W afer sta rt Incoming Si QA NA N…

MIL-STD-883F

METHOD 5004.11

18 June 2004

APPENDIX A

ATTACHMENT 1

Example 2 - Reliability Scenario

Characterization of particles at a gate oxide preclean operation showed that the particles contributed by the operation tend

to be small (0.2 microns) and vary in concentration from 0.02 d/cm

to 0.8 d/cm

depending on how heavily the station is

utilized. Defect density increased as the number of wafers processed through the station increased.

Wafers from this operation were selected such that some of them had low defect densities (approximately 0.3 d/cm

) and

the remainder had high defect densities (approximately 0.8 d/cm

). These wafers were processed through the line and the

die from these wafers subjected to high voltage stress testing. The results of the tests were that the low and moderate

defect density groups showed levels of gate leakage consistent with the historical process baseline. The high defect density

die show gate leakage that was 3 times that of the historical baseline and resulted in barely acceptable failure rates.

As a result of this characterization, a particle monitor was implemented at gate oxide preclean with an upper limit of 0.6

d/cm

to allow some safety margin from the gate leakage problems seen at 0.8 d/cm

. However, due to resource limitations,

this monitor can only be run once every shift (approximately every 12 hours). It is likely that the movement of material in the

line will lead to the station occasionally exceeding its control limits between monitors. A second preclean station is

scheduled to be installed in about three months. This station will provide enough capacity to prevent wafer-volume related

out-of-control particle conditions at the gate preclean operation. In order to ensure that no material with bad gate oxide is

shipped during the interim period (before the new station comes on-line), a manufacturer imposed screen (high-voltage

stress test) is used on all material processed between a failing monitor and the last known good monitor at this operation.

In order to show that the screen is effective, particle monitors are processed through the station with every lot of wafers.

This test is done for a period of time sufficient to yield multiple lots at various defect densities. Die from each of these lots

are processed through the high-voltage screen. The results show that the screen is 100 percent effective at detecting the

lots with defect densities greater that 0.6 d/cm

. The results show a solid correlation between gate oxide preclean defect

densities and gate oxide leakage levels. The screen is then used to augment station particle level data and remains in place

until the second station is installed and qualified.

MIL-STD-883F

METHOD 5004.11

18 June 2004

APPENDIX A

ATTACHMENT 2

EXAMPLE OF DEFECT DETECTION FOR KEY PROCESS STEPS:

PROCESS STEP

PRODUCT MONITOR EQUIPMENT MONITOR RELIABILITY

MONITOR

Wafer start Incoming Si QA NA NA

EPI Laser surface particle Gas flow/pressure, NA

scan. chamber temp

Start Oxide Oxide thickness, laser Tube temp profile, Oxide integrity

surface particle scan. CV, thermocouple cal, test wafers

gas flows, tube particle

checks using laser surface

scan.

Patterning/Well UV light particle insp, Exposure dose, reticle/ LYA

Implant optical pattern insp, pellicle inspection,

e-test parametrics. stepper stage checks

implant dose processor

and voltage calibration,

DI water resistivity.

Particle checks of stepper,

implanter, coat/develop

tracks using laser surface

particle scan.

Active Region Alignment check, optical Exposure dose, reticle/ Oxide integrity

Patterning/Gate Oxide inspection, automated pellicle inspections, test wafers,

(no 2010 equiv.) pattern inspection, UV light stepper stage checks, tube comb/serpentine

and laser surface particle temp profile, CV thermo- test structures,

inspections, in-line SEM CD couple cal, gas flows, DI LYA.

measurement, e-test water resistivity. Particle

parametrics. checks of stepper, diffusion

tube, coat/develop tracks

using laser surface particle

scan.

Poly Dep/Patterning Alignment check, optical and Dep tube pump/vent speed, Comb/serpentine

automated pattern inspection, MFC calibration, gas flows, test structures,

laser surface particle pressures, temperature. buried contact

inspections, in-line SEM CD Expose dose, reticle/pellicle check, LYA.

measurement, e-test checks, stepper stage checks.

parametrics. DI water resistivity.

Particle checks on poly tube,

stepper and coat/develop

tracks using laser surface

particle scan.

MIL-STD-883F

METHOD 5004.11

18 June 2004

APPENDIX A

ATTACHMENT 2

Patterning/ Alignment check, optical Exposure dose, reticle/ LYA.

S/D Implant pattern inspection, UV pellicle inspection,

light or laser surface stepper stage checks.

particle inspections. implant dose processor

E-test parametrics. and voltage calibration,

DI water resistivity.

Particle checks of stepper,

implanter, coat/develop

tracks using laser surface

particle scan.

ILD 1/Patterning Alignment check, auto- Exposure dose, reticle/ Refractive

mated pattern inspection, pellicle inspection, index.

UV light and laser surface stepper stage checks. % phosphorus.

particle inspection, e-test ILD deposition system Film integrity

parametrics. In-line SEM temp/pressure. MFC tests (break-

CD measure. calibration, gas flows. down, etc.).

DI water resistivity. LYA.

Particle checks on stepper,

coat/develop tracks and ILD

deposition system.

Metal 1/Patterning Alignment check, auto- Expose dose, reticle/ Contact chains,

mated pattern inspection, pellicle inspection, Metal-to-poly

laser surface particle stepper stage checks. contact, Metal-to-

inspection, metal Metal dep thickness, diff contacts,

resistivity/specularity, RGA of dep system, electromigration

In-line SEM CD measurement gas flows, pressures, monitors, metal

and electrical CD measure, pump/vent rate checks, CDs (at end of

e-test parametrics. metal resistivity/ line), step

specularity. Particle coverage. LYA.

checks on metal dep

system, stepper and

coat/develop tracks using

laser surface scan.

ILD 2/Patterning. Similar to ILD1. Similar to ILD1. Similar to ILD1.

Metal 2/Patterning Similar to Metal 1 Similar to Metal 1 Similar to Metal 1

with addition of Via

chains, Metal 2-to-

Metal 1 contact.

Glassivation/ Coarse alignment check, Glassivation thickness, Acid bath for

Bond pads optical inspection of phos content, temp, glass integrity.

bond pads to ensure pressure and flows. Acoustic micro-

clearing and of passivation Exposure dose, stepper scopy.

for cornerholes. stage parameters. Part-

icle checks on all equip.

Backside prep/ Post-tape visual, post- Grind rate check, grind Warpage and

Chrome/Gold Dep/ grind visual, post-detape pressure check. thickness checks.

E-test/Sort visual (all optical). Evaporator pressure/leak Die cracking and

Warpage check, thickness rate checks, RGA, power adhesion

check. Chrome/gold thickness and gas flows. Warpage monitors at

checks, visual for backside and thickness checks on assembly.

appearance post-dep. Post- test wafers.

sort visual (optical).