Low Stress n It Ride

7/28/2019 Low Stress n It Ride

1/34

Low Stress Nitride- Analysis of new recipes LSN850 and LSN900

- Analysis of Nanospec at > 5000 A nitride

thicknesses

Eehern Wong

[email protected]

Nancy Latta, Hiten Parmar, Ravneet Kaur, Jim McVittie


2/34

Introduction:

New LSN850/LSN900 Recipes:

The motivation for characterizing new recipes for low stress nitride is a call to improve

film quality. Although we are meeting the low stress requirements of 50 MPa with ourcurrent low stress nitride recipe LONH378, the film quality is poor, with the landscape

ridden with bubbles such as the ones below:

On the left we have a cluster of bubbles at 2500X, and on the right we can see that these

bubbles are as large as 5 um in diameter.

These are beautiful SEM pictures showing the bubbles, but even to a standard labmicroscope these bubbles are apparent and abundant.

The hypothesis for these bubbles was that we were running the Dichlorosilane:Ammonia

(DCS:NH3) ratio too high during deposition with the recipe LONH378. We were runningat a ratio of 14:1, although literature told us that we could drastically decrease the ratio byincreasing temperature a minor amount. LONH378 ran at 800 C during deposition. The

goal of the new recipes was to see how low we could decrease the ratio DCS:NH3 while

maintaining:1) Stress ~50 MPa

2) Temperature 850 C or 900 C

3) Minimal / No bubbles

The runs we tested are listed in the next section.


3/34


4/34

LSN800/LSN900 New Recipe Analysis:

The Test:

At 850 K, nitride runs were done at the following ratios with recipe LSN850:

5:1, 6:1, 6.3:1

At 900 K, nitride runs were done at the following ratios with recipe LSN900:

2:1, 4:1, 4.2:1

Key Figures:

1) All tests were done for a deposition time of30 minutes.

a) All furnace temperatures and pressures hit targets during deposition time. The

temperatures during deposition were observed every 5 minutes and were within+/-1.32% max.

2) Thicknesses were measured.

a) Nanospec measurements at 5 points.b) Ellipsometer measurements at 5 points.

c) Typical thicknesses were around

i) 3000 A at 850 Cii) 5000 A at 900 C

d) Typical refractive index were around

i) 2.2 at 850 Cii) 2.1 at 900 C

3) Backsides were etched at AMT Etcher for approximately 5-10 minutes depending on

the thickness of the film.

a) Etch rate is approximately 600-700 A / minute for films at both 850 K and 900 K

4) Stress measurements taken at FSM Stress Tester

a) At 850 K, tests were done at the following ratios:

i) 5:1 ~225 MPaii) 6:1 ~100 MPa

iii) 6.3:1 ~100 MPa

b) At 900 K, tests were done at the following ratios:i) 2:1 ~500 MPa

ii) 4:1 ~90 MPa

iii) 4.2:1 ~40 MPa

5) Film quality observed in darkfield ("Champagne bubbles").

a) Pictures taken (see Appendix)b) Wafers overall have fewer bubbles than pervious recipe LONH378

c) Increasing temperature decreases bubbles

d) Wafers with a baffle in front had significantly fewer bubbles


5/34

The Experiment:

Correction Conversion:

The formula used to calculate the corrected gas flows for the Tylan systems are listed

below, courtesy of Jim McVittie:

1.04*NH3 + 0.5 = type into Tycomm NH3

0.91*DCS + 0.6 = type into Tycomm DCS

NH3 = the gas flow rate of ammonia

DCS = the gas flow rate of dichlorosilaneNH3+DCS = 200 before the correction rate

Example:Ratio R = 3

DCS:NH3 = 3 = 150:501.04*50 + 0.5 = 52.5 = type into Tycomm NH3

0.91*100 + 0.6 = 91.6 = type into Tycomm DCS

So the runs and ratios entered are as follows:

Ratio Theoretical DCS Flows Theoretical NH3 Flows Tycom DCS Flows Tycom NH3 Flows

LSN850 5 167 33 151 35

6 171 29 157 30

6.3 173 27 158 29

LSN950 2 132 67 121 70

4 160 40 146 42

4.2 162 38 148 41

Runs and Results:

The primary objective of this experiment was to validate a process that would increasethe film quality of nitride films, while keeping film stress minimal. Ideally we would like

to have low stress of 50 MPa, since the old recipe LONH378 could achieve this, although

film quality suffered.

We adjusted 2 degrees of freedom: 1) deposition temperature and 2) DCS:NH3

deposition ratio. The important results are summarized below:

Ratio Stress (MPa) Thickness (A) Dep Rate (A/min) RI

LSN850 5 232.81 2886 96.2 2.151

6 118.74 2918 97.3 2.229

6.3 107.94 2135 71.2 2.198

LSN950 2 505.75 5433 181.1 2.002

4 89.64 4374 145.8 2.294

4.2 43.81 4152 138.4 1.930


6/34

(Note: stress numbers are from FSM stress tester, thickness/deposition rates are from

Ellipsometer)

Film Stress:

The key figure to pull from this chart is that in this range of ratios and temperatures,

stress tends to be almost linear. At 900 C it is very linear and makes it to 50 MPa with aratio of 4.2, while at 850 C the stress seems to flatten out towards 100 MPa for ratios

around 6.

Stress at 850 C (right) and 900 C (left)

232.81

118.74107.94

505.75

89.64

43.81

0.00

100 .00

200.00

300.00

400.00

500.00

600.00

0 1 2 3 4 5 6 7

Ratio (DCS:NH3)

850 C

900 C

Deposition Rate:

Thicknesses at 850 C tend to be around 3000 A, while depositions at 900 C tend to be

around 5000 A. But there is a slight decrease in deposition rate as the DCS:NH3 increase.

The deposition rates for 900 C looks relatively linear again, while that for 850 C looks to

also decrease, but not by much.


7/34

Corrected Deposition Rate at 850 C (right) and 900 C (left)

96.2 97.3

71.2

181.1

145.8138.4

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

0 1 2 3 4 5 6 7

Ratio (DCS:NH3)

DepositionRate(A/min)

850 C

900 C

Refractive Index:

Its hard to say much about refractive indices, especially for 900 C. As shown below, at850 C the refractive index of the film is pretty close to 2.2, while at 900 C the fluctuates

from 1.9 to 2.3 just on average!

Refractive Index at 850 C (right) and 900 C (left)

2.151

2.229

2.198

2.002

2.294

1.930

1.900

1.950

2.000

2.050

2.100

2.150

2.200

2.250

2.300

2.350

0 1 2 3 4 5 6 7

Ratio (DCS:NH3)

850 C

900 C


8/34

Film Quality:

In the previous process, LONH378, there were complaints that films had bubbles in

them. Their typical density is seen below with a standard microscope under darkfield:

Although not perfect, there are a lot more clean wafers under the new processes LSN850and LSN900. The image below shows a directory structure of all the wafers tested. The

wafers with Clean as a subdirectory indicate a wafer with no bubbles.


9/34

Nearly all wafers deposited at 900 C came out clean, especially increasing the ratio,

which we would do to decrease stress anyways. The wafers at 850 C turned out slightly


10/34

more sporadic, with about 50% of them coming out clean. But of the other 50% which

were not clean, most tended to contain smaller bubbles at a lower density as well. Here isan example of one done at 850 C at a ratio of 5:1 at higher magnification (LONH378 is

shown on the left):

At a ratio of 6:1 they were even cleaner:

At 6.3:1, however, they seemed to come out worse, but still better than LONH378:

For a complete catalog of film quality photos, see Appendix B.


11/34

A nice tabled summary of all this information is given below, courtesy of Nancy Latta:

Nitride Study Results

Program SIN5.5 LSN8:1 LS850 3.9:1 LS900 1.6:1

Time 03:00:00 03:00:00 00:30:00 00:30:00Temp 785C 785C 850C 900C

DCS Flow 164.9sccm 172.6sccm 138sccm 110.7sccm

NH3 Flow 30.0sccm 21.6sccm 37sccm 73.3sccm

Lo NH3 Flow 0 0 0 0

Process Pressure 454.2mT 455.7mT 436.1mT -

Thickness 6032-6106A 5714-5754A 2522-3303A 4575-6048A

Refractive Index 2.159-2.164 2.229-2.236 2.070-2.189 1.843-2.078

Stress 593-573Mpa 223-236Mpa 214-259MPa 536-450MPa

Bubbles No Yes

KOH Etch - - - -

HF Etch - - - -

Program 850 6.3:1 850 6:1 850 5:1Time 00:30:00 00:30:00 00:30:00

Temp 850C 850C 850C

DCS Flow 158sccm 156.6sccm 151sccm

NH3 Flow 29sccm 30.2sccm 35sccm

Lo NH3 Flow 0 0 0

Process Pressure 252.9mT 298.2mT -mT

Thickness 2046-2208A 2736-2818A 2490-2956A

Refractive Index 2.178-2.208 2.240-2.271 2.165-2.209

Stress 88.79-122.59Mpa 69.91-158.51Mpa 214.15-258.66Mpa

Bubbles Some Little Some

KOH Etch - - -

HF Etch - - -

Program 900 4.2:1 900 4:1 900 2:1

Time 00:30:00 00:30:00 00:30:00

Temp 900C 900C 900C

DCS Flow 148sccm 146sccm 121sccm

NH3 Flow 41sccm 42sccm 70sccm

Lo NH3 Flow 0 0 0


Thickness 3730-4421A 4079-4374A 4364-6370A*

Refractive Index 2.158-2.214 2.183-2.276 1.788-2.089*


Bubbles No Very Little Very Little

KOH Etch - - -

HF Etch - - -

Note: Thickness and refractive index range chosen from Ellipsometer values with > 12. As falls below12, Ellipsometers ability to resolve thickness and refractive index also falls drastically to the point that we

should not trust its result (see Jim McVittie).

* The for LSN900 @ 2:1 was not recorded, but just looking at the data, the thicknesses seem alright,

while a more reasonable range for refractive index would be 2.052-2.089


12/34

Wafer 1

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10

1 m i n u t e E t c h e s a t A M T

Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 2

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 3

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 4

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Loc1

Loc2

Loc3

Loc4

Loc5

Nanospec vs. Ellipsometer Thickness Experiment (LONH378 Nitride Specific):

People have been wondering which of these two machines to trust. When measuring

oxides, these two machines tend to calculate same values, but with nitride (in particular,

LONH387), they tend to give very different results. The following test was done to

decide which to trust with large films at least. Somewhere in the neighborhood of 7000 A 8000 A was deposited on 4 wafers. It was measured by both Nanospec and

Ellipsometer, and then etched by the AMTEtcher in spurts of 1 minute. AMT is known to

be very consistent in its etching rate, so running the same program over and over again,especially within the same day, should create a very linear chart if we plot thickness each

time. Below are measurements taken by Nanospec after each 1 minute etch:


13/34

Notice that for all 4 wafers, there is a knee at approximately 5000 A. For thin layers of

nitride (~3000 A), Ellipsometer and Nanospec are actually pretty close, especially whenyou manually type in the refractive index (that Ellipsometer calculates) into Nanospec. In

addition, what Nanospec does is it sweeps a range of wavelengths, plots their response,

and fits it with the best theoretical curve. These curves are sinusoidal in shape, with the

plotted curve typically below the theoretical curve. When films are thin, the smallest peakof the calculated curve is upwards of 90% of the theoretical curve. As film thickness

increases, the calculated curve drifts lower. When the curve was 9000 A initially, the

curve was only 75% that of the theory.

This being the case, if we assume Nanospec does a good job with thin nitride films, we

can extrapolate the lower line in these graphs to give the actual thickness of the nitride.Doing so shows that Nanospec is about 1000 A too high for wafers with over 5000 A of

nitride. Ellipsometer also cycles, typically every 1500 A, so comparing the extrapolated

Nanospec value with the correct cycle of Ellipsometer shows that the two machinesconcur quite well. Below is a table of the absolute difference:

| (Ellip-(Nano-1000))mod(Ellip Cycle) | Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Waf1 67.7 508.7 7.2 14.2 410.2 201.6

Waf2 389.5 662.4 214.3 62.5 227 311.1

Waf3 144 179 100.3 236.7 303.5 192.7

Waf4 454.9 138.4 164.2 271.4 334.9 272.8

(@ ~9000A) 244.6

Waf1 82.1 79 147.3 1274.3 37.8 324.1

Waf2 19 55.9 152.6 89.7 36.1 70.7

Waf3 155.5 85.6 245 321.8 79.6 177.5

Waf4 19.8 4.3 0.8 19 32.2 15.2

(@ ~8500A) 146.9

So a good process might be to:

1) Measure refractive index with Ellipsometer2) Measure thickness with Nanospec, using the RI value found

3) If the majority of thickness measured is greater than 5000 A, subtract 1000 A

4) Return to Ellipsometer and use this as an estimate of expected thickness


14/34

Conclusions:

New LSN850/LSN900 Recipes:

The new recipes are an improvement on LONH378 in terms of film quality, but are still

not perfect. The recipes that come closest to providing 50 MPa of stress with reasonablebubbleness are:

LSN850, R = 6.3:1LSN900, R = 4.2:1

If bubbles is a large concern, running at 900 C (LSN900) at ratio 4.2:1 is a good choice,or LSN850 at ratio 6:1.

All depositions at 850 C and 900 C hit target pressures and temperatures with no reportedproblems.

Nanospec Thickness Measurements:

The following process should be followed when measuring thick nitride films:

1) Measure refractive index with Ellipsometer2) Measure thickness with Nanospec, using the RI value found

3) If the majority of thickness measured is greater than 5000 A, subtract 1000 A4) Return to Ellipsometer and use this as an estimate of expected thickness


15/34

Appendix A: Nitride Study Results


16/34

Nitride Study Results

Program SIN5.5 LSN8:1 LS850 3.9:1 LS900 1.6:1

Time 03:00:00 03:00:00 00:30:00 00:30:00

Temp 785C 785C 850C 900C

DCS Flow 164.9sccm 172.6sccm 138sccm 110.7sccm

NH3 Flow 30.0sccm 21.6sccm 37sccm 73.3sccm

Lo NH3 Flow 0 0 0 0

Process Pressure 454.2mT 455.7mT 436.1mT -

Thickness 6032-6106A 5714-5754A 2522-3303A 4575-6048A

Refractive Index 2.159-2.164 2.229-2.236 2.070-2.189 1.843-2.078

Stress 593-573Mpa 223-236Mpa 214-259MPa 536-450MPa

Bubbles No Yes

KOH Etch - - - -

HF Etch - - - -

Program 850 6.3:1 850 6:1 850 5:1

Time 00:30:00 00:30:00 00:30:00

Temp 850C 850C 850CDCS Flow 158sccm 156.6sccm 151sccm

NH3 Flow 29sccm 30.2sccm 35sccm

Lo NH3 Flow 0 0 0


Thickness 2046-2208A 2736-2818A 2490-2956A

Refractive Index 2.178-2.208 2.240-2.271 2.165-2.209


Bubbles Some Little Some

KOH Etch - - -

HF Etch - - -

Program 900 4.2:1 900 4:1 900 2:1

Time 00:30:00 00:30:00 00:30:00Temp 900C 900C 900C

DCS Flow 148sccm 146sccm 121sccm

NH3 Flow 41sccm 42sccm 70sccm

Lo NH3 Flow 0 0 0


Thickness 3730-4421A 4079-4374A 4364-6370A*

Refractive Index 2.158-2.214 2.183-2.276 1.788-2.089*


Bubbles No Very Little Very Little

KOH Etch - - -

HF Etch - - -

Note: Thickness and refractive index range chosen from ellipsometer values with > 12.

As falls below 12, ellipsometers ability to resolve thickness and refractive index also

falls drastically to the point that we should not trust its result (see Jim McVittie).

* The for LSN900 @ 2:1 was not recorded, but just looking at the data, the thicknessesseem alright, while a more reasonable range for refractive index would be 2.052-2.089.


17/34

Appendix B: Nitride Film Quality Photos


18/34

LONH378 7000 A:

10X

50X

100X

200X

LSN850 R = 5 : Waf 7:

10X

50X

100X

200X

LSN850 R

10X

50X

100X

200X


19/34

LSN850 R = 5 : Waf 9:

10X

50X

100X

200X

LSN850 R = 6 : Waf 18:

10X

50X

100X

200X

LSN850 R

10X

50X

100X

200X


20/34

LSN850 R = 6 : Waf 24:

10X

50X

100X

200X

LSN850 R = : Waf 72:

10X

50X

100X

200X

LSN850 R

10X

50X

100X

200X


21/34

LSN850 R = 6.3 : Waf 7:

10X

50X

100X

200X

LSN850 R = 6.3 : Waf 9:

10X

50X

100X

200X

LSN900 R

10X

50X

100X

200X

N/A (Bas


22/34

LSN900 R = 2 : Waf 11:

10X

50X

100X

200X

LSN900 R = 4 : Waf 19:

10X

50X

100X

200X


23/34

Appendix C: Relevant Excel Sheets

for LSN850/LSN900


24/34

Date Name Recipe Dep Time Nanospec Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Nit7 LSN850 00:30:00 3357 3369 3211 3264 2281 3096.4

Nit8 5:1 3145 3184 3192 3185 3174 3176.0

Nit9 2834 2847 2853 2821 2800 2831.0

3034.5

Nit10 LSN900 00:30:00 6177 6136 6012 6359 6187 6174.2

Nit11 2:1 4694 4652 4588 475 4604 3802.6

Nit12 4694 4652 4588 4751 4604 4657.84878.2

2/8/2002 Nit16 LSN850 00:30:00

D18-17-16D Nit17 6:1

Boat 2 Nit18

2/11/2002 Nit19 LSN900 00:30:00 RI=2.001 (default) 5212 5055 5136 5147 5144 5138.8

D21-20-19D Nit20 4:1 5465 5371 5420 5404 5436 5419.2

Boat 2 Nit21 4535 4736 4968 5000 4950 4837.8

5131.9

2/17/2002 Nit22 LSN850 00:30:00

D24-23-22DD Nit23 6:1

Boat 2 Nit24

Nit25

2/18/2002 Waf71 LSN850 00:30:00 RI=2.001 (default) 2969 2996 2999 3085 3067 3023.2

D73-72-71DD | --74-- | Waf72 6:1 3221 3172 3188 3199 3196 3195.2

Boat 2, Boat 1 Waf73 3136 3070 3090 3092 3095 3096.6

Waf74 3750 3634 3665 3689 3674 3682.4

3249.4

3/13/2002 Q6 LSN850 00:30:00 2259 2338 2344 2290 2323 2310.8

D8-7-6DD Q7 6.3:1 2461 2457 2448 2415 2433 2442.8

Boat 2 Q8 2364 2343 2337 2326 2325 2339.0

2364.2

3/20/2002 Q9 LSN900 00:30:00

--11,10,9-- Q10 4.2:1

Boat 2 Q11


25/34

Name Ellipsometer Loc1 Loc2 Loc3 Loc4 Loc5 Avg Ellipsometer Loc1 Loc2 Loc3 Loc4 Loc

Nit7 Thicknesses 2956 3210 3354 3500 3493 3302.6 Refractive Index 2.165 2.115 2.057 2.009

Nit8 2860 2822 2842 2817 2819 2832.0 2.199 2.189 2.194 2.209

Nit9 2561 2490 2508 2524 2529 2522.4 2.189 2.182 2.184 2.186

2885.7

Nit10 5810 6056 6102 6126 6145 6047.8 2.052 2.083 2.084 2.086

Nit11 5136 5226 5858 5792 6370 5676.4 2.017 1.554 1.923 1.936

Nit12 4364 4581 4645 4656 4628 4574.8 2.075 2.084 2.088 2.0875433.0

Nit16 5765 4287 4334 4346 4335 4613.4 2.224 2.233 2.245 2.255

Nit17 4358 4346 4345 4333 4344 4345.2 2.278 2.263 2.270 2.273

Nit18 4296 4265 4265 4263 4276 4273.0 2.267 2.255 2.258 2.277

4410.5

Nit19 4056 4309 4283 4268 4251 4233.4 2.459 2.276 2.306 2.299

Nit20 5043 4494 4317 4618.0 2.139 2.332

Nit21 4079 4325 4373 4203 4374 4270.8 2.183 2.215 2.215 2.267

4374.1

Nit22 2598 2691 2751 2760 2736 2707.2 2.228 2.232 2.246 2.263

Nit23 2802 2772 2779 2768 2785 2781.2 2.275 2.263 2.264 2.277

Nit24 2728 2684 2693 2696 2909 2742.0 2.265 2.254 2.259 2.264

Nit25 3551 3593 3537 3570 3546 3559.4 2.123 2.060 2.083 2.100

2947.5

Waf71 2593 2724 2739 2758 2744 2711.6 2.223 2.233 2.239 2.245

Waf72 2819 2790 2788 2787 2793 2795.4 2.264 2.254 2.263 2.266

Waf73 2745 2701 2707 2710 2720 2716.6 2.265 2.252 2.257 2.263

Waf74 3545 3642 3553 3530 3546 3563.2 2.120 2.027 2.085 2.102

2946.7

Q6 2046 2173 2173 2162 2169 2144.6 2.178 2.194 2.196 2.194

Q7 2208 2185 2164 2151 2175 2176.6 2.208 2.203 2.203 2.200

Q8 2123 2090 2062 2057 2087 2083.8 2.204 2.199 2.194 2.195

2135.0

Q9 3889 3857 3755 3730 3777 3801.6 2.188 2.169 2.165 2.158

Q10 4434 4073 4031 3832 4092.5 2.214 1.209 1.866 1.946

Q11 4421 4712 4392 4725 4562.5 2.216 2.177 1.192

4152.2


26/34

Extra DataTube Pressure Process Temperature

Nit7

Nit8

Nit9

Nit10

Nit11

Nit12

Nit16 Base: 20.5 5 min = 848.7, 855.5, 861.2

Nit17 Leak: 34.6

Nit18 Process: 5 min = 289.1, 15 min = 297.0, 25 min = 292.0

max = 1.32% off 850

Nit19 Base: 16.1 29 min = 899.5, 905.7, 910.8

Nit20 Leak: 27.3

Nit21 Process: 25 min = 319.4, 29 min = 319.4

max = 1.2% off 900

Nit22 Base: 24.9 5 min = 848.9, 855.1, 861.0

Nit23 Leak: 33.2

Nit24 Process: 5 min = 298.9, 15 min = 301.3, 25 min = 301.3

Nit25 max = 1.32% off 850

Waf71 Base: 23.4 5 min = 848.5, 854.9, 861.2

Waf72 Leak: 33.2

Waf73 Process: 5 min = 298.9, 15 min = 301.3, 25 min = 301.3

Waf74 max = 1.32% off 850

Q6 Base: 19.0 TempL: 5 min = 848.9, 10 min = 849.5, 15 m

Q7 Leak: 27.3 TempC: 5 min = 855.3, 10 min = 855.5, 15 m

Q8 Process: 5 min = 251.0, 10 min = 252.0, 15 min = 251.0, 20 min = 252.9, 25 min = 252. TempS: 5 min = 860.8, 10 min = 860.8, 15 m

max = 1.27% off 850

Q9 Base: 19.0 TempL: 5 min = 898.9, 10 min = 898.7, 15 m

Q10 Leak: missed TempC: 5 min = 906.1, 10 min = 905.7, 15 m

Q11 Process: 5 min = 268.6, 10 min = 269.6, 15 min = 267.6, 20 min = 269.6, 25 min = 271. TempS: 5 min = 909.8, 10 min = 911.8, 15 m

max = 1.31% off 900


27/34

Extra DataInit Curvatur Final Curvat Nanospec Extra Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Nit7

Nit8

Nit9

Nit10

Nit11

Nit12

Nit16

Nit17

Nit18

Summary

Nit19 RI=2.25 (default) 4636 4518 4557 4594 4574 4575.8

Nit20 4859 4785 4817 4813 4829 4820.6

Nit21 4059 4059 4098 4420 4410 4209.2

4535.2

Nit22

Nit23

Nit24

Nit25

Waf71 RI=2.240 2622 2752 2773 2622 2782 2710.2

Waf72 RI=2.260 2882 2837 2855 2860 2861 2859.0

Waf73 RI=2.260 2805 2743 2765 2784 2780 2775.4

Waf74 RI=2.090 3625 3526 3561 3588 3572 3574.4

2979.8

Q6 2.10E+02 330.11

Q7 3.60E+02 438.86

Q8 -1.00E+03 359.27

Q9 1.10E+02 299.22

Q10 -3.30E+02 623.97

Q11 1.10E+02 891.6


28/34

Summary Ratio Stress (MPa) Thickness (A) Dep Rate (A/min) RI

LSN850 5 232.81 2886 96.2 2.151

6 118.74 3435 114.5 2.229

6.3 107.94 2135 71.2 2.198 2.193

LSN950 2 505.75 5433 181.1 2.002

4 89.64 4374 145.8 2.294

4.2 43.81 4152 138.4 1.930 2.075

Note: we have a "corrected" deposition rate because

one of the terms in the thickness at R 6:1 seemed to be one cycle off: ~1550 A

(Corrected Ratio Stress (MPa) Thickness (A) Dep Rate (A/min) RI

LSN850 5 232.81 2886 96.2 2.151

6 118.74 2918 97.3 2.229

6.3 107.94 2135 71.2 2.198

LSN950 2 505.75 5433 181.1 2.002

4 89.64 4374 145.8 2.294

4.2 43.81 4152 138.4 1.930

Ratio Theoretical DCS Flows Theoretical NH3 Flows Tycom DCS Flows

LSN850 5 167 33 151

6 171 29 157

6.3 173 27 158

LSN950 2 132 67 121

4 160 40 146

4.2 162 38 148


29/34

Stress at 850 C (right) and 900 C (left)

232.81

118.74107.94

505.75

89.64

43.81

0.00

100.00

200.00

300.00

400.00

500.00

600.00

0 1 2 3 4 5 6 7

Ratio (DCS:NH3)

Stress(MPa)

850 C

900 C

Deposition Rate at 850 C (right) and 900 C (left)

96.2

114.5

71.2

181.1

145.8138.4

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

0 1 2 3 4 5 6 7

Ratio (DCS:NH3)


850 C

900 C

Corrected Deposition Rate at 850 C (right) a

181.1

145.8138.4

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

0 1 2 3 4 5

Ratio (DCS:NH3)


Refractive Index at 850 C (right) and 90

2.002

2.294

1.930

1.900

1.950

2.000

2.050

2.100

2.150

2.200

2.250

2.300

2.350

0 1 2 3 4 5

Ratio (DCS:NH3)

RefractiveIndex(RI)


30/34


31/34

Name Recipe Dep Time Nanospec Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1 LONH378 04:00:00 (No AMTEtch) 8773 9274 8856 8271 9133 8861.4

Q2 RI = 2.5 9277 9328 9400 9331 9402 9347.6

Q3 8987 9292 9300 9052 9332 9192.6

Q4 9267 9409 9463 9412 9374 9385

Q5 9298 9401 9449 9452 9458 9411.6

9334.2

Q1 LONH378 (04:00:00) (1 min AMTEtch) 8082 8607 5409 7515 8537 7630Q2 RI = 2.5 8544 8690 5793 8710 8733 8094

Q3 8343 8638 8509 8408 8727 8525

Q4 8609 8749 8796 8762 8738 8730.8

1089.25 8244.95

Q1 LONH378 (04:00:00) (2 min AMTEtch) 7384 8010 7685 7047 7833 7591.8

Q2 RI = 2.5 7948 8071 8104 8170 8162 8091

Q3 7731 8045 7945 7807 8079 7921.4

Q4 8011 8127 8224 8120 8070 8110.4

316.3 7928.65


Q2 RI = 2.5 7319 7422 7532 7450 7469 7438.4

Q3 7175 7424 7390 7164 7415 7313.6

Q4 7356 7427 7532 7513 7451 7455.8

693.8 7234.85

Q1 LONH378 (04:00:00) (4 min AMTEtch) 6179 6833 6451 5817 6863 6428.6Q2 RI = 2.5 5472 6855 6879 6866 6962 6606.8

Q3 6457 6830 5475 6606 6901 6453.8

Q4 5508 5573 6929 6949 6832 6358.2

773 6461.85


Q2 RI = 2.5 6074 6268 5084 6247 6287 5992

Q3 4608 6052 6122 4669 6051 5500.4

Q4 6108 6170 6285 6271 6225 6211.8

718.25 5743.6


Q2 RI = 2.5 4249 4431 4486 4491 4496 4430.6

Q3 3960 4369 4257 4059 4345 4198

Q4 5457 4335 4490 4461 4362 4621

1319.3 4424.3


Q2 RI = 2.5 3614 3818 3813 3814 3860 3783.8

Q3 3342 3645 3679 3452 3646 3552.8

Q4 3616 3691 3838 3864 3739 3749.6

813.7 3610.6


Q2 RI = 2.5 2990 3228 3282 3237 3357 3218.8

Q3 2721 3170 3117 2925 3207 3028

Q4 2975 3115 3265 3252 3226 3166.6

551.1 3059.5

Average Etchrate/minute

Average Thickness

These have two nanospec measurements, just by taking 2 measurements one right after another.

The one listed is the smaller one. The other one is ~1200 A higher for both

Conclusions: Most etch rates are in the area of 638 A (this is the average slope of the line we graph)

There are basically two slopes, one for thicknesses above ~5000A and one for thicknesses below ~5000A

Extrapolating the 2 lines, the higher line is approximately 1000A-1500A greater than the lower line

For thickness < 5000 A, the nanospec matches ellipsometer very well


32/34

Wafer 1

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10

1 minute Etches at AMT

Thickness(A) Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 2

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Thickness(A) Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 3

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Thickness(A) Loc1

Loc2

Loc3

Loc4

Loc5

Wafer 4

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 2 4 6 8 10


Thickness(A) Loc1

Loc2

Loc3

Loc4

Loc5


33/34

Name Delta Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1

Q2

Q3

Q4

Q5

Q1 691 667 3447 756 596 1231.4Q2 733 638 3607 621 669 1253.6

Q3 644 654 791 644 605 667.6

Q4 658 660 667 650 636 654.2

951.7

Q1 698 597 -2276 468 704 38.2

Q2 596 619 -2311 540 571 3

Q3 612 593 564 601 648 603.6

Q4 598 622 572 642 668 620.4

316.3

Q1 1838 651 637 671 504 860.2

Q2 629 649 572 720 693 652.6

Q3 556 621 555 643 664 607.8

Q4 655 700 692 607 619 654.6

693.8

Q1 -633 526 597 559 466 303Q2 1847 567 653 584 507 831.6

Q3 718 594 1915 558 514 859.8

Q4 1848 1854 603 564 619 1097.6

773

Q1 1758 693 1993 545 803 1158.4

Q2 -602 587 1795 619 675 614.8

Q3 1849 778 -647 1937 850 953.4

Q4 -600 -597 644 678 607 146.4

718.25

Q1 684 561 -795 1890 1773 822.6

Q2 1825 1837 598 1756 1791 1561.4

Q3 648 1683 1865 610 1706 1302.4

Q4 651 1835 1795 1810 1863 1590.8

1319.3

Q1 597 1765 1925 657 513 1091.4

Q2 635 613 673 677 636 646.8

Q3 618 724 578 607 699 645.2

Q4 1841 644 652 597 623 871.4

813.7

Q1 611 551 393 495 608 531.6

Q2 624 590 531 577 503 565

Q3 621 475 562 527 439 524.8

Q4 641 576 573 612 513 583

551.1

This is the average of all reasonable etch rates: 638.375


34/34

Extra Data Ellipsometer Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1 ~"9000 A" 7585 6416 6483 7224 6384 6818.4

Q2 6495 6337 6989 7059 7363 6848.6

Q3 6422 7551 7594 6449 7531 7109.4

Q4 6444 7061 7085 6951 7430 6994.2

Q5 6449 7190 6481 7023 6785.75

6934.488

Q1 ~"8500 A" 8391 7778 8846 9149 7818 8396.4Q2 8967 9194 7825 7814 7797 8319.4

Q3 8366 9170 9196 9174 9250 9031.2

Q4 9031 7784 7794 7805 7782 8039.2

8446.6

Ellip Cycle Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1 ~"9000 A" 1436.3 1349.3 1380.2 1395.8 1338.8 1380.1

Q2 1392.5 1326.7 1196.7 1209.5 1266 1278.3

Q3 1421 1303 1311.7 1366.3 1298.5 1340.1

Q4 1368.1 1209.6 1213.8 1189.6 1278.9 1252.0

Q5 1312.6

Q1 ~"8500 A" 1226.9 1447 1429.9 1359.7 1442.8 1381.3

Q2 1442 1448.1 1439.7 1441.7 1444.1 1443.1

Q3 1178.5 1446.4 1442 1444.2 1443.4 1390.9Q4 1441.8 1439.3 1437.2 1438 1440.2 1439.3

1413.6

Nano-1000A Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1 ~"9000 A" 7773 8274 7856 7271 8133 7861.4

Q2 8277 8328 8400 8331 8402 8347.6

Q3 7987 8292 8300 8052 8332 8192.6

Q4 8267 8409 8463 8412 8374 8385.0

Q5 8298 8401 8449 8452 8458 8196.7

Q1 ~"8500 A" 7082 7607 4409 6515 7537 6630.0

Q2 7544 7690 4793 7710 7733 7094.0

Q3 7343 7638 7509 7408 7727 7525.0

Q4 7609 7749 7796 7762 7738 7730.8

7245.0

| (Ellip-(Nano-1000))mod(Ellip Cycle) | Loc1 Loc2 Loc3 Loc4 Loc5 Avg

Q1 ~"9000 A" 248.3 1189.9 387.4 348.8 1267.4 688.4

Q2 3 989.1 1179.1 147 493 562.2

Q3 277 438 394.3 129.6 502.5 348.3

Q4 1281.3 71.2 49.6 1107.8 613.8 624.7

Q5 555.9

Q1 ~"8500 A" 299.9 211 577.2 274.3 714.2 415.3

Q2 173 440.1 592.3 350.3 427.9 396.7

Q3 5.5 382.4 68 678.2 397.4 306.3

Q4 175.8 474.3 435.2 476 471.8 406.6

381.2

Documents

Low Stress n It Ride