Line-by-line comments 4-apr-08

16 The ID does NOT provide charged particle track reconstruction (it
would be great if a detector could do that and output tracks rather than
hits, but haven't yet figured out how)

35-50 Replace "excellent", "good", "very good" with numbers where
possible, and simply remove where not possible. For example "good 3D
vertexing" should become "3D vertexing". "Excellent transverse impact"
should become "order 10um transverse impact", etc.

43 and secondary interactions -\> , secondary interactions, and
degradation of calorimeter energy resolution.

46 or 10\^15 units -\> and 10\^ units (to be referred to as the lifetime
dose)

48 the requirement ... confirmed by -\> this is based on

53 smallest -\> smallest achievable

55 dose -\> ionizing dose

55 500kGy -\> the lifetime dose

67 monitoring and cooling -\> monitoring, optical I/O, and cooling

Table 1: Number of pixels -\> Number of channels (not the same thing!)

Table 2: ditto

113: I would remove sentence "the required radiation tolerance..."

Fig 5 caption: add "Sensor bias supply not shown"

120 no new paragraph.

120 the cells of the sensor array are collected -\> the sensor is
integrated

123 serial star -\> star (what is a serial star?)

134 system uses commercial components -\> system uses a combination of
customized commercial and fully custom components.

134 delete "adapted to...pixel detector"

137 maximum -\> absolute maximum (this is a standard term)

138 To interface between...implemented -\> The optical links are custom
made using commercial diode and laser array bare die with custom driver
integrated circuits and packaging.

153 The column readout -\> The FE-A column readout

154 Hits are -\> Hits were

160-165 I have a big problem with such vendor references. I strongly
suggest to remove all vendor names from the paper. Otherwise you need to
get permission in writing from each vendor, and in any case you surely
won't get it from some so some vendors will be mentioned and not others.
I see no possible value in including vendor names and product part
numbers in such an overview paper. This should be called a "radiation
qualified 0.8um CMOS technology"

167 left the collaboration with -\> pushed the collaboration towards

Table 3: Add FE-H before FE-I1. 0.8um radiation qualified CMOS

Figure 6 caption: Floor plan -\> Schematic diagram.

Figure 6 caption: add "Not to scale".

188 DC feedback -\> feedback capacitor with a current source continuous
reset

188 mA -\> uA

190 bias current of the feedback --\> continuous reset

190 delete ",used to discharge...capacitor"

190 The feedback system -\> The implementation

195 a pulse width -\> a discriminator pulse width

196 over-Threshold, -\> over-Threshold (TOT),

200 comparator -\> discriminator

201 Comparator -\> Discriminator

229 cells with data -\> occupied cells

233 to transfer a single hit -\> at which bytes can be transferred

239 at a speed -\> at a selectable speed

246 Hit information is -\> Once

246 , and waits there -\> , hit information waits there

247 at the correct time...for the hit -\> at a time corresponding to the
LE time stamp plus a programmable trigger latency

249 received triggers -\> received one or more L1 triggers

250 readout sequence in which... -\> readout sequence, as described
under the next heading. (move rest of para. to next heading)

255 Keep first sentence, delete rest of this paragraph (redundant with
next heading).

270 Add new paragraph: During the readout sequence the EOC buffers are
scanned... (paragraph moved from previous heading).

283 The noise is 160e -\> The noise with the sensor load (50um x 400um
pixel) is 160e

285 depends -\> depend

290 600kGy -\> the lifetime dose

292 pixels) -\> pixels at -7C)

294 12 inch -\> 8 inch

297 -\> The wafers were probed using custom setups on semi-automatic
probe stations. Each chip was fully exercised including measurement of a
reference calibration capacitor value using a dedicated circuit only
available at probing. This removed process variations from the charge
and threshold calibration scale. Test time was approximately 30 hours
per wafer and the selection was based on cuts on over 30 analog and
digital parameters. \[reference- I think Aldo may have a conference
proceeding we can reference- should ask him\]. Every chip was probed
again after dicing the bumped wafers using custom vacuum chucks to hold
up to 60 chips at one time that could be probed like a wafer. The
failure rate of chips after dicing was 2% (this would have translated
into 30% module rework rate if this step had been skipped). \[reference:
here we should reference a conf. proceeding or paper by Igor Volobouev,
who developed this technique for CDF, in addition to what we may have on
it (maybe Bonn)\]. Additionally, the indium bumped chips were
photographed during probing and 160 images per chip (containing all the
bumps at 50X magnification) were archived for future reference.

362 add footnote for LVDS type signals "Low voltage differential but not
necessarily conforming to the LVDS standard"

368 2-bit wide serial -\> 2-bit parallel

373 add: "the 40MHz beam crossing clock using multi-drop LVDS"

379 command, -\> command (11101),

386 the circuit were -\> the circuit was

387 Upset -\> Upset (SEU).

393 delete ", the total power is 290mW" (anyone reading this far can
multiply 145x2 in their head)

395 -\> The wafers were probed at a commercial vendor using ATLAS
supplied test vectors. The chip includes special outputs to be able to
test the full state machine "phase space" with such vectors. (Giovanni
should rephrase this).

825-830 This is a horrible introduction that says noting at all. Can you
simply remove it?

832 resistivity bulk -\> resistivity n-type bulk

836 all charges... -\> charge carriers generated by ionizing particles
passing through the active volume.

836 concept -\> design

838 The pixel sensor...n-bulk -\> The n-bulk thickness is 250um and the
resistivity between 2 and 3 Ohm.cm

838 250um thickness to the checked- I think it's more like 260. Actual
value with errors would be preferable.

838 "400x50um\^2" this is impossible- it violates unitarity. The actual
size of the implants should be given, with two values for length
corresponding to 400 and 600 um pixels

839 implantations -\> implants

840 88.9% -\> 8/9

841 11.1% -\> 1/9

842 implantations -\> implants

852 in the bulk ... against -\> have been introduced into the bulk to
increase tolerance against

872 delete "demands precise mask steps"

873 micrometers. -\> microns, which makes the manufacturing process
demanding.

875 The 250um thick...3Kohm/cm -\> The sensors

949 1.86 -\> 1.64

949 100um -\> \~100um

949 foil -\> ("Flex hybrid")

951 foil -\> circuit

956 \~190um -\> 195 +/-10 um (sigma)

956 by back-side -\> by wafer back-side

959 flexible-hybrid kapton foil -\> Flex hybrid

960 foil -\> Flex hybrid

961 flex-kapton circuitry -\> Flex hybrid

963 dispersion on the flex circuit -\> variation

964 The flex circuit...sensor bias -\> The back side of the Flex hybrid
must be pinhole free because it lays directly on top of the high voltage
side of the sensor. A multiple solder mask layer was therefore used and
all parts were tested to hold of 1000V.

965 The kapton material ... (500KGy) -\> Since all module components
must withstand the lifetime radiation dose, polyimide was used as the
Flex hybrid base material with adhesiveless metalization.

968 (NTC) resistor placed -\> (NTC) thermistor loaded.

970 A complete ... 500 KGy. -\> After lifetime dose a module is expected
to draw 1.3A at 1.7V analog and 0.9A at 2.1V digital currents, including
pigtail and Flex hybrid but not microcable voltage drops, plus 1mA at
600V sensor bias, for a total power of 4.7W. However voltages may have
to be increased to recover performance up to a maximum of 6W.

977 The sensor pixels ... (about 11%) which -\> 8/9 Of the sensor pixels
have dimensions of 50 um x 400um, while 1/9

980 These off-side sensor pixels are connected... 4+4 -\> Each of these
special pixels is ganged through metal lines on the sensor with one of
4+4

981 delete "in addition to ... underneath"

983 These special pixels ... increased sensor capacitance -\> Thus there
are 5 distinct pixel types with decreased performance due to added input
capacitance and ambiguities (see 6.6). These are: long (10.6%), ganged
(2.2%), inter-ganged (1.6%), long ganged (0.3%), and long inter-ganged
(0.2%).

992 get -\> be

992 for 20cm integrated circuit wafers -\> for FE-I3 wafers

995 The integrated circuit wafers ... flip-chip process -\> The dicing
was performed before thinning by making 250um deep cuts in the 700um
thick wafers. Separation of the chips occurs towards the end of the
back-grinding operation (dicing before grinding). This was done to
obtain high quality diced edges.

1002 "which provides self alignment" I have doubts about this since
force is used to press the chip and sensor together. I don't see how
force and self alignment are compatible. Should ask Norbert.

1009 The bump pitch -\> No under bump metalization is needed. The bump
pitch

1017 television -\> video

1021 solder and indium -\> solder (45%) and indium (55%)

Fig. 25 not the best. Why not put the SEM x-section of soldered bumped
chip instead?

1040 once again remove footnote listing vendor name. Are we going t list
all vendors or just selected ones?

1049 zero insertion force -\> 30-pin surface mount (not ZIF by a long
shot)

1051 use thin copper...which are -\> have the micro-cable

1056 the glue is deposited -\> silicone strip adhesive was used

1058 remove vendor reference 11 (it's completely wrong anyway)

Fig 28 This is not a picture! It is the same Daniel Dobos CAD model
shown in fig 23! I can send you a good picture of a disk module (since
fig 23 shows the barrel module a disk module might be appropriate).

1065 A ranking value...of the detector -\> This was done by ranking the
modules as explained later, rather than using a cut bases selection and
treating all selected modules as equal.

1066 In this calculation different weights are assigned to quantities
such as the number of missing or shorted bumps, minimum digital voltage
for error free operation, sensor bias current, number of reworked wire
bonds, etc.

1070 is done correctly -\> produced test bonds exceeding a minimum pull
force (every module had a number of spare bonds that were pull tested).

1096 A problem in the potting -\> A systematic problem in the
encapsulation (remove vendor footnote! The problem was not due to this
product anyway!)

1097 which was corrected during production -\> . Correcting this problem
required the rework of a number of modules, and such a rework carried a
ranking penalty.

Fig.29 The thresholds are in fact not uniform for the entire module as
can be seen form the fact that the fit is a horrible match to the data.
The data look in fact like the sum a few Gaussians with slightly
different means. One should probably fit to two Gaussians with ratio of
areas fixed to 1:8 (the ratio of normal pixels to other pixels).

1118 The number of dead channels... this function includes: -\> Modules
were ranked using a single value calculated from the test results. In
this calculation different weights are assigned to each variable
considered, dead channels from source data carrying unit weight. The
information combined in the ranking value includes:

1120+ add bullet: "Number of bad channels, including source scan
results, digital tests, and other analog measurements."

1122 remove "penalties for"

1124 any repair operations performed, including number of reworked wire
bonds

1125 function -\> value

1125 remove "of the ranking function"

1126 bump -\> excess

1126 remove "in the ranking distribution"

1127 potting -\> encapsulation

Fig 31 IZM -\> solder, SELEX -\> indium

Table 6 yield -\> fraction

Table 7 ditto

1203 600V -\> 600V sensor bias

Table 8 Do we have to mention ON and CIS? Can we say Vendor A and Vendor
B instead?

1280 operating -\> sensor

1288 Interpretation of depletion in heavily irradiated silicon is
tricky. Can a sensor expert comment look at this and see if there is a
different phrasing with reference to sensor paper that is more
appropriate?

1290-1549 impeccable

1560 photography -\> photograph

1609 additional -\> dedicated

1609 keep them at -\> actively regulate their temperature at any chosen
value up to 30C.

1612 through -\> additional

1633 occupancy values need units

1635 ditto