The Carolinas SMTA “New Component Technologies”

OVERVIEW• Component Trends

– 01005– LED– PoP

• Printing• Placement• Reflow• Rework• Inspection

Component Trends

Component Trends

-The new smallest device is an 01005 -0.010” X 0.005”-0.4mm X 0.2mm -Just 1/4 the size of an 0201!

Component Trends• LED’s

– Wide range of sizes– Concave or convex lens– Solar PV can use similar

package style– 2012 ??– Applications such as:

• Cell phones• Light bulb replacement• Street lights• Automotive• Everywhere!

Component Trends

• PoP-Literally an IC package or packages on top of an already placed IC package

• Three step process• Gel flux or “dipping”

paste– Two ways to process

• With standard SMT assy.• As a separate process

New Component Trends=

New Assembly Challenges

• Printing process• Equipment capabilities• Stencil design• Type of paste

• Placement equipment• Placement accuracy• Component feeding• Nozzle design• Placement pressure• Component centering

• Reflow process• Oven profile• Component self alignment

Printing Process• Equipment Capabilities

• Print Accuracy• Print Repeatability• Print Quality

• Stencil Design• Aperture Size• Stencil Thickness• E Form or Laser cut• Foil material

• Paste Choice• Lead or No Lead• Types 3, 4, 5

Printing Process

• LED’s and PoP are not significantly affected• 01005 size vs. Printer accuracy

– 0.010” X 0.005”• Printer must have an accuracy of 0.008” (20 micron) +• Stencil must have same tolerance• PCB stretch?

Printing Process• 01005 Stencil design factors

– Thickness typically 3 mils (2.5-3.5 per IPC 7525-A)• Effects on other parts?• Paste release

– Reduction typically 10% (5% for LF)• 1 mil on this PCB (8x10 mil pad)

– Electroformed technology– Aperture Area Ratio

• Aperture area WXLWall area W+LX2Xthickness

Printing Process

• Type IV Solder paste mesh size is optimal for 01005 and PoP.– Effect on other parts– Solder balling

• Type III is usually best for LED’s• Leaded vs No Lead

Pick Process -PoP is not a problem -LED’s must present flat -01005 Component feeding

• As the component size keeps decreasing, so does the ability to reliably supply components to the machine.

• Feeder advance-must be consistent• Auto correct-must assure pick is in the

center of the component• Component presence-need method

other than vacuum (laser) to insure the part is there

Placement Process

• Placement accuracy• Most studies agree that the placement accuracy of the

pick and place machine needs to be 50 micron (0.05mm or 2mils) in X and Y and 10 degrees for theta.

Typical PoP assembly process

PCB

•Print solder paste

Layer 1

•Place directly on PCB

Layer 2

•Dip in flux or dippable paste

•Measure stack height

•Place on stack

Fluxer

15

(1) Placement on the first tier (3) Flux coating (second

tier)

(2) Mounted component height measurement

(4) Placement on the second tier (first chip)

POP Placement ProcessPOP Placement Process

POP Placement Example

POP Placement ProcessPOP Placement Process

Placement Process

Component centering-Laser or Vision?-The laser typically has approximately 3 x

the pixels as a CCD or Digital camera. -Laser is faster

-LED and 01005 use laser-PoP use vision

Placement ProcessLaser Technology“String Art”-The nozzle rotates the component through the laser finding the edge of the component by creating a shadow on the Laser Receiver. Based on the outline made by the String Art, the machine recognizes the difference between the nozzle location and component center, then adjusts the placement position.

Illuminates

Light receiving elements

Center of Nozzle

String Art

Placement Process

• Nozzle design– Very critical for LED and 01005

• “Blow Off”?• Local fiducials?• Placement pressure• PCB stretch-”OPASS”

– Offset Placement After Solder Screening

Example of Component Placement

How It Works

Using the local fiducial function, the machine will check the solder paste position relative to the pad locations

Correct for fiducials

Components are placed centered on the solder paste print, not the pads

Placement of component on misaligned stencil or stretched PCB

Placement centered on solder paste print, not pads

3）

2）

1）

JUKI’s Solution

Corrected placement between PCB pads and print misalignment

☆

Machine self-contained

Traditional Placement on PCB pads

Fiducial mark

Self Contained in Machine

2-1

1608 lands

2012 lands

1-1

1-2

2-1 2-3

Placement centered on paste

Solution

2-3

Placement corrected for print offset

1 ） Self-alignment is improved by placing on paste

→ Results are good up to about 0.1mm (half size of 01005), but neighboring pads can affect larger offsets

print 0.10 / placement 0

NG

print 0.10 / placement 0.10

OK

print 0.16 / placement 0

NG

print 0.19 / placement 0.19

OK

01005 chip 0201 ＆ 0402 chip

6/16Comparison of Placement Offset Results good even with larger offset

Placement Process-01005’s

OPASS-offset placement after solder stenciling

-compensate for these problems. • Billboard• Skewed• Tombstone

Reflow Process

• Oven profile– Minimal impact unless LF– Cold solder on 01005 (N2?)– Solder balls on larger parts

• Component self alignment• Tombstoning

Rework

• 01005-yea right• PoP-hot gas or IR station

– Must remove the whole package• LED-conductive tweezers or hot air pencil

– Hot gas station destroys the part

Inspection

• 01005-typically need an upgraded camera on AOI systems

• PoP-very difficult. Must have X Ray and 3D is preferred (at least have oblique view)

• LED-no problem

Summary

• All aspects of the PCB assembly process are affected

• Different parts have different challenges• New components present new challenges but

also new opportunities• Utilize your partners-Circuit Technology and

many others can help you. WWW.circuittechnology.com

• What’s next??