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SEMI G78-0699 © SE MI 1999 12 Suggested Graph s for X-Offset and Y- Offset (see Appen dix 1 for exam ples): X-Offset Y-Offset LOTX + D-D-X LOTY + D-D-Y LOTX LOTY LOTX - D-D-X LOTY - D-D-Y Average Die X- Offset (3) Averag…

SEMI G78-0699 © SEMI 199911

From the last die

of wafer 10 until

the wafer is stored

in the wafer boat

and the boat is

free to be removed

from the prober

(LDT2C)

Start Stopwatch,

prober

From pushing

"start" to the

testing of the first

die on the first

wafe

(

S2FDT

OCR

)

From beginning to

end of automatic

probe-to-pad

alignment

procedure

Note that this

procedure is to be

performed prior to

wafers 1,2,5 & 8

Using the stopwatch's

"split" function, record

the following times:

APTPA

PTPA

From pushing

"start" to the

testing of the first

die on the second

wafer

(S2FDTW2)

From the last die

of wafer 3 to the

first die of wafer 4

(A2B)

Stop stopwatch at

this time

(TTCC)

1 2 3 4 5 6 7 8 9 10

10.6

10.7

10.9

Figure 9

Timing Procedure

11 Introduction

11.1 The Probe Mark Analysis System recognizes the edge of the bond pad passivation opening and the probe

mark, draws a best-fit rectangle around the probe mark and passivation opening, and returns the four distances, Left,

Right, Bottom and Top to a text file. The center position of the best-fit rectangle can be used to represent the center

of the scrub mark. An offset of this center of scrub mark from the center of the bond pad can be calculated as

follows:

2/)(

TopBottomPadYoffset

RightLeftPadXoffset

−=

(1)

The variation of this offset from pad to pad, die to die, wafer to wafer and setup to setup captures most of the

process variations.

11.2

PMA Data Analysis

11.2.1 We will use a sampling scheme of 9 wafers per lot, (3 setups per lot, 3 wafers per setup), 12 dies per wafer

and 24 pads per die as an example for discussing the data analysis algorithm. The first step of doing data analysis is

to obtain the offsets for all the pads that have been sampled using Eqn.(1). This means that the offsets

yoff

xoff

padmdielwafksetjloti

t][PadYoffse

t][PadXoffse

,,,,

(2)

for a pad m on die l, wafer k, under setup j in lot i are known.

Step 1

Calculate Average Die Offset for the lot [LOTX or LOTY] (3)

,,,,,,,

padmdielwafksetjlotidielwafksetjloti

yoffyoff

xoffxoff

(3)

Step 2

Calculate D-D-X or D-D-Y = 3σ of Average Die Offset [LOTX] and [LOTY](3)

These die offsets are again treated on the equal basis. A 3σ value is calculated and becomes our Die-to-Die

Variation (D-D-X, D-D-Y) for the entire lot.

LOTX + D-D-X, LOTX - D-D-X = Total Prober X-Error Range (3σ)

LOTY + D-D-Y, LOTY - D-D-Y = Total Prober Y-Error Range (3σ)

SEMI G78-0699 © SEMI 1999 12

Suggested Graphs for X-Offset and Y-Offset (see Appendix 1 for examples):

X-Offset Y-Offset

LOTX + D-D-X LOTY + D-D-Y

LOTX LOTY

LOTX - D-D-X LOTY - D-D-Y

Average Die X-Offset (3) Average Die Y-Offset (3)

12 Data Collection Table

12.1 The following data are to be recorded about the test environment:

Title Description Values

Installed (Yes/No)

Tester - Prober Interface

If installed, Total Pogo

pin force (nominal, calculated)

pounds

Present [docked] (Yes/No)Tester

If present, state manufacturer and

model

Wafer Nominal Die Size (Small, Medium

or Large)

Needle count

gramsNominal force per needle

ounces

micronsDiameter of needle tip

mils

micronsNeedle pitch (within a single row or

column)

mils

Number of needle tiers

Size of needle array in the X

direction (left-to-right when facing

prober (from the operator position))

inches

mmSize of needle array in the Y

direction (away and towards the

operator relative to the center of the

probe card)

inches

Probe Card

Diameter of probe card

inches

ºCSet point / Temperature of chuck

during test

ºF

Soak time, probe card (if test

temperature is other than ambient)

minutes

Test Temperature

Soak time, prober (if other than

ambient)

minutes

Title Description Values

microns

X-direction

mils

microns

DUT spacing

Y-direction

mils

micronsZ clearance

mils

micronsOverdrive

mils

Tester-Prober communications method

OCR on? (Y/N)

SEMI standard font? (Y/N)

OCR Variables

# of retries allowed

Definitions for formulae:

Variable Description Values

DPW

Die Per Wafer

Test Time (minimum value of 1.0 seconds) seconds

Data Collected Description Values

A2B Last die (Wafer A) to first die (Wafer B) time seconds

S2FDT Time from pushing "Start" to First Die Test with OCR

turned off

seconds

S2FDT

OCR

Time from pushing "Start" to First Die Test with OCR

turned on

seconds

S2FDTW2 Time from pushing “Start” to First Die Test, Wafer #2 seconds

LDT2C

Time from end of Last Die Test to Cassette free to remove

from prober

seconds

TTCT Total Time to Complete Test seconds

TTAA Time To Auto-Align the probe needles with the die bonding

pads

seconds

3) (TTAALDT2C S2FDTW28)(A2B9)DPW(TTTTCT

D2D

×−−−×−××−

Calculated Results Values

D2D seconds