01005 Assembly Process, Materials and Tooling

01005 Assembly Process, Materials and Tooling 01005 Assembly Process, Materials and Tooling Denis Barbini, Ph.D. Universal Instruments Corporation Advanced Process Lab Denis Barbini, Ph.D. Universal Instruments Corporation Advanced Process Lab IntroductionIntroduction 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 NecessityA 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 Component01005 Component How small is it?How small is it? Size Comparison Grain of Salt Penny Pencil 01005s mixed with black pepper. Market InformationMarket Information 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 Weight Area Price Mobile Phone Evolution SOURCE: Prismark Partners LLC 0603 0402 0201 01005 Bottom View Shrinking FootprintShrinking Footprint Common Name Capacitor Footprint (1206) 3216 3.2 mm x 1.6 mm in 1970 (0603) 1608 1.6 mm x 0.8 mm in 1983 (0402) 1005 1.0 mm x 0.5 mm in 1990 (0201) 0603 0.6 mm x 0.3 mm in 1997 (01005) 0402 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 AvailabilityPart Availability • Availability and price go hand in hand. • Limited values: cap or resistor • A simple search on supplier website for 01005, 0201 and 0402 with interesting results • Placement yields are not as high as larger size parts which only serve to drive the cost of using this part even higher. • In certain applications increased functionality of the device outweighs the increased cost of the part. $30/reel$45/reel$580/reel 0.0020.0030.0387$ 3000+3000+185In Stock 6000+6000+641 Search Results 0402020101005 Vendors: • Murata • HDK • Rohm • Panasonic • Kamya • Tayio 0201 / 01005 Assembly Issues0201 / 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 GreatlyComponent Size/Shapes Vary Greatly Capacitor (Murata) Outline and electrode vary by each maker. They can influence recognition, placement accuracy and pick-up rate. Resistor (KOA) Resistor (Matsushita) Resistor (Hokuriku) TapesTapes 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. • 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 TapesTapes • Designed specifically for 01005 and 0201’s • Reliable feeding mechanisms at maximum machine speeds • Special shutter/peeler for 01005 and 0201 0402 0201 01005 feeders0402 0201 01005 feeders 0402 0201 0201 01005 FeedersFeeders • 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 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 PastePrinting 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 RatioArea Ratio Area Ratio: comparing areas of paste contact inside the aperture = A ÷÷÷÷ B IPC–7525: Complete solder transfer achieved at Area Ratios > 0.66 PCB stencil A B B PCB stencil A B B SUBSTRATESUBSTRATE PASTE DEPOSIT PADSOLDER MASK STENCIL SEPARATION (V) Area Ratio = Aperture Opening Area Aperture Wall Surface Area STENCIL 4953.71.0631651561115 6602.750.7941652081115 8252.20.6351652601115 9901.80.5861803121115 >1.5>.66 Paste volume Aspect Ratio width/thickness Area Ratio Printed area/wall area Stencil Thickness Area of Printed area Area of Aperture walls Aperture Length Aperture Width Area RatioArea Ratio Typical 0201 ApertureTypical 0201 Aperture Area Ratio 0201Area Ratio 0201 0% 20% 40% 60% 80% 100% T r a n s f e r E f f i c i e n c y 1.00.50.25 0.75 1.250 Area Ratio 0% 20% 40% 60% 80% 100% T r a n s f e r E f f i c i e n c y 1.00.50.25 0.75 1.250 Area Ratio 0.66 Recommended 0201 using 5-mil stencil 3242.30.5648114499 2562.00.5046412888 24330.7538110899 1922.70.673649688 >1.5>.66(mils)(mils)(mils) Paste Volume Aspect Ratio width/thickness Area Ratio pad area/wall area Stencil Thickness Area of pad Area of aperture walls Aperture length Aperture length Area RatioArea Ratio Typical 01005 ApertureTypical 01005 Aperture Area Ratio 01005Area Ratio 01005 0% 20% 40% 60% 80% 100% T r a n s f e r E f f i c i e n c y 1.00.50.25 0.75 1.250 Area Ratio 0% 20% 40% 60% 80% 100% T r a n s f e r E f f i c i e n c y 1.00.50.25 0.75 1.250 Area Ratio 0.66 Recommended 01005 using 4-mil stencil Solder Paste PrintingSolder Paste Printing Type 3 Type 4 Type 5 Pad size: 11x11, 5 mil space between pads Aperture size 11x11 Stencil thickness: 4 mil Area ratio .69 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 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 defectsTypical solder joint defects Component PCB Solder joint Component attachment pad Component PCB Solder joint Component attachment pad Mis-placed component Solder paste Attachment pad Insufficient solder volume Excessive solder volume Component mis alignment Typical defectsTypical 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, 01005Solder Mask Related Defects, 01005 Source: 01005 assembly process—from the board design to reflow Global SMT & Packaging – September 2008 Solder Mask Related Defects, 01005Solder 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 ReflowSolder Paste Reflow � Forced Convection oven � Air or Nitrogen. Process window tighter for Air. � Orientation has little effect on defect rates Pad / Stencil Design, 01005Pad / Stencil Design, 01005 “Standard”apertures centered on pad. (1 mil cutback) BFG CEG BEG BFG CEG BEG Choice 1 Choice 2 Choice 3 6 9 9 9 11 11 BFG CEG BEG BFG CEG BEG Choice 1 Choice 2 Choice 3 6 9 9 9 11 11 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. 0.012” 0.009” Attachment Pad Component 0.015” 0.018” Pad Design, 0201Pad Design, 0201 Paste deposit Pad on PCB Component 16 mil 9 mil 1 5 -1 8 m il 12 mil 3 mil 11 mil Stencil design • 5 mil (125 mm) thick stencil maximum • 11*15 mil aperture (275*380 mm), • 3 mil grab minimum (75 mm), application specific 0201 Stencil Design0201 Stencil DesignDesign 0201 Experiment data0201 Experiment data Assembly Defects by Attachment Pad Width and Assembly Process Type 0 100 200 300 400 500 600 12 15 18 Pad Width (mils) N u m b e r o f S o l d e r J o i n t D e f e c t s No-Clean, Air Reflow Water-Soluble, Air Reflow No-Clean, Nitrogen Reflow 0201 Experiment data0201 Experiment data Assembly Defects by Attachment Pad Length and Assembly Process Type 0 100 200 300 400 500 600 8 12 16 Pad Length (mils) N u m b e r o f S o l d e r J o i n t D e f e c t s No-Clean, Air Reflow Water-Soluble, Air Reflow No-Clean, Nitrogen Reflow 0201 Experiment Data0201 Experiment Data Assembly Defects by Attachment Pad Spacing and Assembly Process Type 0 20 40 60 80 100 120 140 160 180 200 9 12 Attachment Pad Spacing (mils) N u m b e r o f S o l d e r J o i n t F a i l u r e s No-Clean, Air Reflow Water-Soluble, Air Reflow No-Clean, Nitrogen Reflow Screen Printer Process 0201Screen 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” 0.009” 0.012” 0.015” 0.008” 0.009” 0.012” 0.018” Pad spacing • Component distance > 7 mil (175 µµµµm) • 4 mil pad distance minimum, 6 to 8 mils preferred 7 mil 4 mil 0201 Pad Spacing0201 Pad Spacing ConclusionsConclusions 02010201 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 AttendingThank You for Attending Denis Barbini Universal Instruments Advanced Process Lab 603 828 2289 barbini@uic.com