01005 Assembly Process, Materials and Tooling 01005 Assembly

01005 Assembly Process, Materials and Tooling 01005 Assembly
01005 Assembly Process,
Materials and Tooling
Denis Barbini, Ph.D.
Universal Instruments Corporation
Advanced Process Lab
Introduction
Introduction to the 01005
•
History and market information
Availability
Assembly Issues
•
Design
PCB
Tools
Printing
Aperture design
Paste
Placement
nozzles
Feeders
Tape
Reflow
A Challenge Based on Necessity
Chip caps and resistors are among the smallest, simplest and perhaps the
least expensive parts in a printed circuit assembly.
However, they require the most attention by perhaps the most expensive
investment of the assembly process: the placement machine. Printing and
reflow also exert significant influences on the end result.
Developing a process that includes capability for the assembly of 0201
and 01005 components does not have to be a complicated exercise.
Using specific design rules for substrates and stencils, consistent
materials, and the proper tools, an acceptable process can be developed.
01005 Component
How small is it?
Size Comparison
01005s mixed with black pepper.
Pencil
Penny
Grain of Salt
Market Information
Mobile Phone Evolution
Drivers
•
Continued miniaturization of
cell phones, pagers, PDA’s, MP3 players
etc. have driven component sizes down
from 0603 and 0402 to 0201 and 01005.
•
Increased functionality of portable digital
electronics such as cell phones and
notebook computers that continue to
push the envelope of form and
functionality.
•
Smaller capacitors and integration of
components help to achieve the desired
performance levels and customer
expectations
•
Hi Frequency manufacturers are the main
users
•
Higher performance in smaller packages
at the lowest cost.
– This is not always achievable
Area
Weight
Price
SOURCE: Prismark Partners LLC
0402
01005
0201
0603
Bottom View
Shrinking Footprint
Common Name
(1206)
3216
(0603)
1608
(0402)
1005
(0201)
0603
(01005) 0402
Capacitor Footprint
3.2 mm x 1.6 mm in 1970
1.6 mm x 0.8 mm in 1983
1.0 mm x 0.5 mm in 1990
0.6 mm x 0.3 mm in 1997
0.4 mm x 0.2 mm in 2004
•In spite of having equal capacitance the
footprint in 1997 is approximately 1/6
of the size in 1990.
And the 01005 has a footprint of 0.08 mm2 vs.
5.12 mm2 of a 1206 capacitor. That is a
reduction of 98.5%
The 01005 has a footprint of 44% of that of an
0201.
Part Availability
• Availability and price go hand in hand.
01005
0201
0402
• Limited values: cap or resistor
Search
Results
641
6000+
6000+
• A simple search on supplier website
In Stock
185
3000+
3000+
for 01005, 0201 and 0402 with
interesting results
$
0.0387
$580/reel
• Placement yields are not as high as
larger size parts which only serve to
drive the cost of using this part even
higher.
Vendors:
• Murata
• HDK
• Rohm
• In certain applications increased
functionality of the device outweighs
the increased cost of the part.
• Panasonic
• Kamya
• Tayio
0.003
0.002
$45/reel $30/reel
0201 / 01005 Assembly Issues
Printing: Small apertures
•
Stencil clogging, insufficient deposits, deposit size variation, alignment
Placement: Small passives
•
Component size variation
•
Packaging; tapes, feeders, ESD
•
Nozzles, nozzle contamination
•
Speed, placement accuracy, pick issues, placement order
Reflow: Tolerance to above imperfections?
Component Size/Shapes Vary Greatly
Capacitor (Murata)
Resistor (KOA)
Resistor (Matsushita)
Resistor (Hokuriku)
Outline and electrode vary
by each maker.
They can influence
recognition, placement
accuracy and pick-up rate.
Tapes
In general:
• Paper carriers work well for passive components up to approximately 0.9
mm in thickness.
• Beyond the 0.9 mm threshold, paper carrier tapes may be too thick and
stiff, resulting in tough handling and errors when feeding into the SMT
assembly equipment.
Tapes
• The smaller the device the more important Dimensional tolerances become in
ensuring proper feeding and pick-and-place.
• Standard dimensional tolerances for carrier tape pocket dimensions are 100
µm deviation from target.
• However, as component sizes drop, the dimensional tolerance of the
pocket can become more important.
•Larger tolerances for a small component could lead to excessive part
rotation or tilt within the pocket.
•Smaller, more complex components may require tighter tolerances down
to the 50 µm level.
• Unique tooling and precision processing technology enables smaller form
sizes using high-precision tapes.
• Tape pocket-hole-forming down to 0.20 mm will restrict movement and tilting
to allow component placement into pocket cavities accurately during
component insertion applications.
• Tape and feeder interaction is critical to make sure that they deliver the best
accuracy
0402 0201 01005 feeders
• Designed specifically for 01005 and
0201’s
• Reliable feeding mechanisms at
maximum machine speeds
• Special shutter/peeler for 01005 and
0201
0201
0402
0201
01005
Feeders
• Auto Teaching of Tape Pocket and
Pick height to assure accurate Pick
while machine maps feeder index
profile to optimize pick
performance
• .66 mil per pixel resolution camera
01005 Pick and Place
01005 Pick and Place
• Caps and Resistors are different thicknesses
• Resistors are thinner more opportunity for nozzle contact with paste
CAP
Resistor
Printing and Solder Paste
Solder Paste:
Powder size: type 3 $, 4 $$ or 5 $$$
Stencil:
Thickness: 3, 4 or 5 mil thick
Material: SS, Nickel, Invar
Type: Laser cut, Efab
Squeegees: Metal or Enclosed Print Head
Area Ratio
Area Ratio: comparing areas of paste
contact inside the aperture = A ÷ B
B
stencil
B
A
PCB
IPC–7525: Complete solder transfer
achieved at Area Ratios > 0.66
Area Ratio
Typical 0201 Aperture
Aperture
Width
Aperture
Length
Area of
Aperture
walls
Area of
Printed
area
Stencil
Thickness
Area Ratio
Printed
area/wall area
>.66
Aspect Ratio
width/thickness
Paste volume
>1.5
15
11
312
180
6
0.58
1.8
990
15
11
260
165
5
0.63
2.2
825
15
11
208
165
4
0.79
2.75
660
15
11
156
165
3
1.06
3.7
495
Aperture Opening Area
Area Ratio =
Aperture Wall Surface Area
STENCIL
STENCIL
PASTE
DEPOSIT
SOLDER MASK
PAD
SUBSTRATE
SEPARATION (V)
Area Ratio 0201
0.66
Transfer Efficiency
100%
0201 using
5-mil stencil
80%
60%
Recommended
40%
20%
0%
0
0.25
0.5
0.75
1.0
Area Ratio
1.25
Area Ratio
Typical 01005 Aperture
Area of
aperture
walls
Area of
pad
Stencil
Thickness
Area
Ratio pad
area/wall
area
Aspect Ratio
width/thickness
(mils)
>.66
>1.5
Paste
Volume
Aperture
length
Aperture
length
(mils)
(mils)
8
8
96
64
3
0.67
2.7
192
9
9
108
81
3
0.75
3
243
8
8
128
64
4
0.50
2.0
256
9
9
144
81
4
0.56
2.3
324
Area Ratio 01005
0.66
Transfer Efficiency
100%
01005 using
4-mil stencil
80%
60%
Recommended
40%
20%
0%
0
0.25
0.5
0.75
1.0
Area Ratio
1.25
Solder Paste Printing
Type 3
Type 4
Pad size: 11x11, 5 mil space between pads
Aperture size 11x11
Stencil thickness: 4 mil
Area ratio .69
Type 5
Pad size 8.8 round, .4mm pitch
Aperture size 9.5 square
Stencil thickness 3 mil
Area ratio .79
What if….Stencil 4 mil = .59 ratio
Paste Positioning on Attachment Pads
Recommend best pad / stencil design combination.
Report assembly yield trends for:
•
•
•
•
Grab (balanced / imbalanced)
Print mis-registration tolerance
Reflow atmosphere (N2 vs. air)
0201 vs. 01005
Typical grab solutions for 0603 and smaller parts
Typical solder joint defects
Component
Insufficient solder volume
Solder joint
Component
PCB
Component attachment pad
Solder joint
PCB
Component attachment pad
Attachment pad
Mis-placed component
Excessive solder volume
Component mis alignment
Solder paste
Typical defects
Open solder joints (tombstone)
Solder beads (solder balls)
Solder bridges
Typical Defects
Tombstoning 0201 vs 01005
N2 reflow comparison. Resistors only. Caps may act differently.
Solder Mask Related Defects, 01005
Source: 01005 assembly process—from the board design to reflow
Global SMT & Packaging – September 2008
Solder Mask Related Defects, 01005
• Solder mask is omitted from beneath the components,
• The height of the solder mask can prevent proper
collapse of the solder joints.
Solder Paste Reflow
Forced Convection oven
Air or Nitrogen. Process window tighter
for Air.
Orientation has little effect on defect rates
Pad / Stencil Design, 01005
“Standard”apertures
centered on pad.
(1 mil cutback)
Minimum trace to trace and pad
to pad spacing for most pcb
manufacturers is .005” for outer
layers.
When posing the question ‘how
tight can I get these little
suckers’, you must do a reality
check and think about what you
are asking for and why.
Pad size tolerances are often
+/-.001” and starting copper
weights are often in the ¼ oz.
range when requesting features
.010” or less.
Choice 1
6
11
BFG
9
Choice 2
CEG
11
Choice 3
BEG
9
9
Pad Design, 0201
0.015”
0.018”
0.012”
0.009”
Component
Attachment Pad
0201 Stencil Design
Stencil design
• 5 mil (125 mm) thick stencil maximum
• 11*15 mil aperture (275*380 mm),
• 3 mil grab minimum (75 mm), application specific
Pad on PCB
Paste deposit
Component
15-18 mil
11 mil
9 mil
12 mil
16 mil
3 mil
0201 Experiment data
Number of Solder Joint Defects
Assembly Defects by Attachment Pad Width and Assembly Process Type
600
No-Clean, Air Reflow
500
Water-Soluble, Air Reflow
400
No-Clean, Nitrogen Reflow
300
200
100
0
12
15
Pad Width (mils)
18
0201 Experiment data
Number of Solder Joint Defects
Assembly Defects by Attachment Pad Length and Assembly Process Type
600
No-Clean, Air Reflow
500
Water-Soluble, Air Reflow
400
No-Clean, Nitrogen Reflow
300
200
100
0
8
12
Pad Length (mils)
16
0201 Experiment Data
Number of Solder Joint Failures
Assembly Defects by Attachment Pad Spacing and Assembly Process Type
200
180
160
140
120
100
80
60
40
No-Clean,
Air Reflow
Water-Soluble,
Air Reflow
No-Clean,
Nitrogen Reflow
20
0
9
12
Attachment Pad Spacing (mils)
Screen Printer Process 0201
•DEK
265GSX
•Print speed 1.0”\sec.
•Metal squeegee blades
•Squeegee angle 60 degree
•Squeegee pressure 2.3 lb\inch
•Print gap 0 (on contact)
•Separation speed 0.02”\sec.
0.008”
0.012”
0.009”
0.015”
0.008”
0.009”
0.012”
0.018”
0201 Pad Spacing
Pad spacing
• Component distance > 7 mil (175 µm)
• 4 mil pad distance minimum, 6 to 8 mils preferred
7 mil
4 mil
Conclusions
0201
Nitrogen reflow (under 50 PPM oxygen tested) can increase assembly defects
under certain conditions
Attachment pad design sensitivity is reduced when using lower activity fluxes and
air reflow
Solder beads can be reduced or eliminated by reducing the amount of solder paste
that is printed under the component
The number of tombstones increases as the distance between solder paste
deposits increase
Component orientation is significantly dependent upon the use of Nitrogen and\or
solder paste flux type
Thank You for Attending
Denis Barbini
Universal Instruments
Advanced Process Lab
603 828 2289
[email protected]
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