Measurement of the latest Tesla wafers at Udine
Summary by Diego Cauz
on behalf of the Udine Group
12th February 2003
2
New Tesla wafers
• We have received 4 Tesla wafers from 2 batches in February:
• 8414-14, 8414-16, 8697-04, 8697-10
Visual inspection (VIS) February
• 8414-14 4-4 4-4 4-4 4-4
correct
• 8414-16 4-4 4-4 4-4 4-4
correct
• 8697-04 4-4 4-4 4-4 4-4
correct
• 8697-10 4-4 4-4 4-4 4-4
correct
mask align (H-V) ID marking Wafer n-side L n-side R p-side L p-side R
Legenda:-“4” means that the 4th vernier (ME-PASS) has problems, specifically the passivation part.-Normal face means lines are bad-Boldface means very bad lines (as sampled on thenext two slides) or lines missing altogether.
4
Wafer 8697-104th pair, horizontal
5
Wafer 8697-104th pair, vertical
6
I-V on diode w/ guard ring (IVD)
• 8414-14 5002.73
• 8414-16 5005.78
• 8697-04 5005.29
• 8697-10 5003.16
Wafer Vbd (V) Iop (nA)
Iop = I(Vop)
February
Vbd = max V(I < 25 nA)
7
C-V on diode w/ guard ring (CVD)
• 8414-14 100 3.6 150 2207
• 8414-16 90 3.7 150 2414
• 8697-04 105 3.7 155 2045
• 8697-10 105 3.7 155 2090
Wafer Vdep Cdep Vop (V) (pF) (V) ( cm)
30 < Vdep (V) < 120 2000 < ( cm) < 5000
Vdep = V(kink in C-V curve)
Cdep = C(Vdep)
Vop = max(150 V, Vdep + 50 V)
February
8
I-V on tiles
• 8414-14 70 500 500 - 1.06 1.06 2
• 8414-16 500 500 490 1.09 1.05 1.05 3
• 8697-04 10 500 500 - 1.05 1.05 2
• 8697-10 60 500 500 - 1.04 1.07 2
Wafer Vbd (V) S good tiles
Vbd > Vop S = I(Vop) / I(Vop-50) < 2
February
9
I-V on SC’s: percent yieldVbd > Vop S = I(Vop) / I(Vop-50) < 2
Wafer good/total
February
• 8414-14 5/6
• 8414-16 6/6
• 8697-04 6/6
• 8697-10 5/6
Total: 91.7 %
10
I-V on MC’s: percent yield
• 8414-14 4/4
• 8414-16 4/4
• 8697-04 4/4
• 8697-10 4/4
Vbd > Vop S = I(Vop) / I(Vop-50) < 2
Wafer good/total
February
Total: 100 %
11
I-t on good tiles (ITS)
• 8414-14-02 1.1
• 8697-10-02 1.05
Wafer-tile S
S = Iend / Istart < 1.3
February
12
I-V on MOS (BOX)
• 8414-14 100 8
• 8414-16 100 8
• 8697-04 100 8
• 8697-10 100 8
Vbd > 50 V
Wafer Vbd (V) delay (s)
regular delay = 2 sVbd = max V(I < 100 pA) > 50 V
February
But funny shapes in three over four cases: see next slide
0 20 40 60 80 100
0.0
10.0p
20.0p
30.0p
40.0p
50.0p
reverse Bias (V)
Cur
rent
(A)
BOX measurementTesla 8697-10, OTS 23
8-s delay
0 20 40 60 80 100
0.0
5.0p
10.0p
15.0p
20.0p
25.0p
30.0p
35.0p
reverse Bias (V)
Cur
rent
(A)
BOX measurementTesla 8697-04, OTS 23
8-s delay
The test is passed, but the shapeis not very nice
14
C-V on MOS (COX)
• 8414-14 278 5.1 53.1 4
• 8414-16 273 5.5 62.6 4
• 8697-04 274 5.2 54.5 4
• 8697-10 269 5.2 53.8 4
Wafer Cox (pF) Cmin (pF) CFB (pF) VFB (V)
Cox = Cmax VFB = V(C nearest to CFB)
February
15
I-V on gate-controlled diode (IVG)
Itop = I(VFB +3 V) Ibot = I(VFB – 3 V)
• 8414-14 282 24.3 258
• 8414-16 862 53.8 808
• 8697-04 414 17.7 369
• 8697-10 482 15.0 467
Wafer Itop (pA) Ibot (pA) Iox(pA)
February
16
I-V on MOSFET (MFE)Wafer Vth p dose
(V) (1012 cm-2)
• 8414-14 30 2.95
• 8414-16 30 2.90
• 8697-04 30 2.91
• 8697-10 30 2.85
2.2 < p (1012 cm-2) < 3.5
February
Vth = max V(I < 100 nA) > 0
But funny shapes in twoe over four cases: see next slide
-10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160-7.0µ
-6.0µ
-5.0µ
-4.0µ
-3.0µ
-2.0µ
-1.0µ
0.0
1.0µ
2.0µ
3.0µ
4.0µ
5.0µ
Gate Bias (V)
Sou
rce
Cur
rent
(A)
MFE measurementTesla 8414-16, MOSFET # 26
-10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
-14.0µ
-12.0µ
-10.0µ
-8.0µ
-6.0µ
-4.0µ
-2.0µ
0.0
2.0µ
Gate Bias (V)
Sou
rce
Cur
rent
(A)
MFE measurementTesla 8697-10, MOSFET # 26
The test is passed, but there isthat funny spike
18
Vpix-V on punch-thru structure (PUT)
Wafer Vpt (V)
• 8414-14 2.92
• 8414-16 2.08
• 8697-04 2.35
• 8697-10 2.50
Vpt = Vpix(Vop) > 3 V
February
19
Planarity measurement (PLA)
• 8414-14 8.4
• 8414-16 11.8
• 8697-04 9.0
• 8697-10 25.5
February
Wafer aplanarity (m)
A < 40 m
20
Conclusions
• Generally the measurements are good, with the following exceptions:– VIS: the passivation lines of the 4th verniers in
the mask alignment pad are very poorly done.– BOX, MFE: funny shape of the data.– PUT: punch-through voltage is less than 3 V,
but this can be due to the known problems we have with this measurement.
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