semi合集-English.pdf - 第6067页

SEMI G10-96 © SEMI 198 6, 1996 4 17.1 A li gn overlay to travel axes w i t h in the resol ution of th e instrument . 17.2 Position leadframe to overlay b y o ptical met hods. 17.3 Ov erla y targets will now be po s i t i…

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SEMI G10-96 © SEMI 1986, 19963
microscope and refocus. The difference in readings is
the downset measurement.
Table 2
A B Destination
P-dip 1 2 Bottom
34 Top
Quad 1 2 1st Quad
3 4 2nd Quad
5 6 3rd Quad
784th Quad
12.3 Repeat this for all tie bars indicated in Table 2.
12.4 All measurements must fall within the
specification that applies.
13 Procedure for Coil Set (See Figure 10)
Equipment — Surface plate, gage pins
13.1 Place the strip on the surface plate, bond target
side down, depressed pad up.
13.2 Slip gage pins under until you find the largest
size that will fit under freely at possible locations
shown. Pin diameter is the coil set measurement, noting
the + or designation of coil set direction per Figure l0.
14 Procedure for Pad Planari ty (Z-Axis) (See
Figure 11)
Equipment — Toolmaker’s microscope (100×
magnification), leadframe fixture.
14.1 Fixture leadframe and establish z-plane as
described in Section 5.5.
14.2 Move to the center of the die-attach pad (3) and
refocus. The focal height difference is the pad planarity
measurement.
15 Procedure for Burrs (X, Y, Z-Axis)
15.1 Vertical Burrs — (See Figure 12.)
Equipment — Toolmaker’s microscope (400×
magnification), leadframe fixture.
15.1.1 Fixture leadframe lead flat down and establish
z-plane as described in Section 5, items 5a and 5b.
15.1.2 Focus the toolmaker’s microscope on point A.
Zero the focal height (z-axis).
15.1.3 Move to the top of the burr (Point B) and
refocus the toolmaker’s microscope. The focal height
difference is the height of the vertical burr.
15.2 Horizontal Burrs (X, Y-Axis) — (See B, Figure
12.)
Equipment — Toolmaker’s microscope (400×
magnification).
15.2.1 Measure the horizontal burrs using the
toolmaker’s microscope in a similar manner to that
described in 15.1.2 and 15.1.3.
15.2.2 Line up the cut edge (Point C) with the 0 center
line on the toolmaker’s microscope. Record the number
on micrometer drum.
15.2.3 Move the stage to align the centerline with the
end of the burr (Point D). The lateral movement
(difference between start/end micrometer reading) will
be the burr dimension.
16 Procedure for Pits, Slug M arks, Tool Marks
(X, Y, Z-Axis), and Horizontal Burrs (See Figure
14)
16.1 Depth (Z-Axis)
Equipment — Toolmaker’s microscope (400×
magnification), leadframe fixture.
16.1.1 Fixture leadframe and establish z-plane as
described in Section 5, items 5a and 5b.
16.1.2 Focus the toolmaker’s microscope on the base
of the material near the defect, then zero the focal
height (z-axis).
16.1.3 Move to the pit, slug mark, or tool mark.
Refocus on the deepest portion. The focal height
difference (z-axis) is the depth of the pit, tool mark, or
slug mark.
16.2 Surface Dimension, Length, Width (X,Y-Axis)
Equipment — Toolmaker’s microscope (400×
magnification), leadframe fixture.
16.2.1 Fixture leadframe and establish z-plane as
described in Section 5, items 5a and 5b.
16.2.2 Line up to edge of the pit, slug mark, or tool
mark on the cross hair. Note the micrometer drum
reading.
16.2.3 Move to the opposite side of the pit, slug mark,
or tool mark. The lateral movement (difference between
start/end micrometer readings) is the pit, slug mark, or
tool mark surface dimension.
17 Procedure for X-Y Dimensional
Measurement
Equipment — Surface lit optical comparator, true
position overlay, metal-to-metal step gage.
SEMI G10-96 © SEMI 1986, 1996 4
17.1 Align overlay to travel axes within the resolution
of the instrument.
17.2 Position leadframe to overlay by optical methods.
17.3 Overlay targets will now be positioned to inspect
lead-flat location.
17.4 Pad outline will be positioned to inspect pad
location.
17.5 Metal-to-metal clearance is evaluated by use of
step gage against leadframe image on comparator
screen.
17.6 Traverse to specified distance to inspect cutoff
position.
18 Method for Coin-Depth Measurement
(See Figure 15)
18.1 Bend sample lead up for accessibility.
18.2 Measure material thickness beyond lead flat.
18.3 Measure material thickness within lead flat.
Difference between two readings is depth of coining.
19 Procedure for Measuring Lead Fatigue
Equipment — Automatic or manual lead fatigue tester
with 8 oz. ± .5 oz. weight.
19.1 Clamp leadframe strip on dambar of test frame
(see Figure 18).
19.2 Clamp 8 oz. weight on bottom-half of lead (see
Figure 19). Clamp must be at least L/2 from lead
shoulder.
NOTE: If lead is clamped too close to shoulder, a reduction in
measured lead strength will result, caused by twisting of
weight.
19.3 Turn on lead fatigue machine and set all counters
at zero.
19.4 Activate lead fatigue machine such that clamp
arm rotates through 90° ± 5° (see Figures 20 and 21).
This will result in actual bend of lead slightly less than
90°, depending on strength of metal.
19.5 Set machine to a two-to-five second cycle. One
cycle defined to be a 90° rotation and back.
19.6 Count number of complete cycles until metal lead
breaks and weight drops into pan.
Figure 1
Lead Twist
SEMI G10-96 © SEMI 1986, 19965
Figure 2
Strip Pitch
Figure 3
Pilot Hole
Figure 4
Pad Tilt