NC676 No Clean Solder Paste
Download the TDS and MSDS for this product.
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INTRODUCTION |
| NC676 No Clean Solder Paste is a new generation halide-free, rosin-based chemistry designed to provide a previously unseen level of repeatability and consistency to the printing process. This paste offers an excellent open time, extended abandon time and good soldering activity with all surface finishes. NC676 meets or exceeds the requirements for ANSI/J-STD -004, -005 as well as all Bellcore test criteria for solder pastes. Residues left behind are clear and maintain a virtually indefinite pin probability life. |
| ATTRIBUTES |
TEST RESULTS |
- Excellent print consistency with Surface Area Ratios (SAR) as low as 0.55 when used with the UltraSlic™ stencil technology
- No Hidden Halides - Completely halogen free by all test standards
- Non-hygroscopic formulation suitable for high RH areas
- Wide reflow window with good solderability on various PCB surface finishes
- Unlimited pin probability and clear post-process residues
- Low voiding/high reliability
- Formulated for fast printing
| PRODUCT INFORMATION |
| Alloys |
SN63 (MP=183°C)
62/36/2 (MP=179°C) |
| Powder Size |
Type 3 and Type 4 Standard
Type 5 available upon request |
| Applications |
Automatic/Manual Printing
Automatic/Manual Dispensing |
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| J-STD-004 (IPC TM-650) Test |
Result |
| Flux Type (per J-STD-004) |
ROL0 |
| Copper Mirror |
Low |
| Halide Test |
<0.05% |
| Silver Chromate |
Pass |
| Fluoride Test |
Zero |
| SIR |
Pass |
| Ion Chromotography |
Zero |
| J-STD-005 (IPC TM-650) Test |
Result |
| Brookfield Viscosity Type 3 |
600,000 |
| Brookfield viscosity Type 4 |
650,000 |
| Slump |
Pass |
| Solder Ball |
Pass |
| Wetting |
Pass |
| Bellcore Test |
Result |
| SIR |
Pass |
| Electromigration |
Pass |
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| COOLING |
| A cooling rate of 2°C-3°C per second is typical for most Sn62 and Sn63 applications. These parameters should be utilized to insure a fine grain solder structure and minimal IMC layer. |
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REFLOW PROFILE |
HEATING |
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A linear ramp of 0.7˚C to 2.0˚C C/second is suggested to gradually remove the solvents and other volatile components in the solder paste. This also helps in minimizing solder balls, beading and bridging from hot slump.
A linear ramp also helps minimize depletion of flux activity which can occur with excessive temperature, and at extended preheat times, and at very high reflow temperatures.
A profile with a soak between 200-210°C for less than 20 seconds can be used to reduce void formation on BGA and CSP devices. (Request FCTA’s profile guide to void reduction).
While a linear profile typically does not produce tombstoning, a short 10-20 second dwell prior to transitioning into the liquidus point of the solder, and minimizing the ΔΤ between soak and liquid temperatures will help minimize tombstoning if experienced.
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PRINTING |
HIGH TEMPERATURE PROFILE |
Stencil aperture design and stencil quality are major factors in achieving excellent print consistency with any solder paste. UltraSlic™ (SAR ≥ 0.45) and Slic™ (SAR ≥ 0.55) stencils from Fine Line Stencil are recommended for optimal print performance, and can be custom designed to minimize rework and improve the yields of any process. Some general stencil aperture design guidelines follow:
• Fine pitch components (≤ 0.020”)
A 0.001” reduction (L & W) to minimize bridging and create proper gasketing between the stencil and SMT pad
• Discrete components
A 0.002” reduction (L & W) for water washable and a 0.002” reduction (L & W), with “U-shaped” home-plates, for no clean to minimize mid-chip solder beads.
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| When Soldering to Au, Pt, Pd, Alloy 42 and Thermally Demanding Assemblies |
| Time Above Liquidus (TAL) |
75 to 90 Seconds |
| Peak Temperature |
225˚C to 230˚C |
| Profile Length |
4 to 4 ½ minutes max
from 45˚C to Profile Peak |
| Cool Down |
2.0˚C to 3.0˚C Per Second Typical |
Soldering hard-to-wet alloys such as Au, Pt, Pd, Alloy 42 leadframe, and heavier OSP coatings can be easily achieved through slight modification of Peak, TAL and Profile Length parameters to overcome secondary eutectic, and lower dissolution rates associated with these alloys.
Densely populated, high layer count, and otherwise thermally demanding PWB’s will also typically require, and benefit from these suggested process adjustments.
Request FCTA’s process bulletin for soldering high-temp alloys
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PRINTER OPERATION |
STANDARD LINEAR PROFILE GUIDELINES |
The following are general
recommendations for stencil printer optimization. Adjustments may be
necessary based on specific process requirements.
| Application |
Recommendation |
| Solder Paste Bead |
2cm (~0.75”) on startup
Add when bead < 1.4 cm (~0.5”)
Maintaining a minimal controlled volume of solder paste on the stencil at all times will ensure paste consistency as well as print process repeatability and reliability |
| Squeegee |
Metal, Slic blade preferred. 60 degrees from
horizontal |
| Speed |
25 to 200 mm/sec (1 to 6 in/sec). Adjust printer for a pull or print-on-demand process |
| Pressure |
0.18-0.27 Kg/cm (squeegee length). Apply only enough pressure to achieve a clean top-side wipe of the stencil surface after each squeegee pass |
| Underside Wipe |
Slic and Ultraslic should exceed > 10
prints/wipe. |
| Stencil Life |
> 8 hours at 30+60% RH and 20-25˚C
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A linear ramp-style profile (Figure 1) is recommended with NC676; however, it will also perform well in ramp-soak profiles. Some general guidelines for a standard linear profile:
| Ramp Rate |
0.7˚C to 2.0˚C Per Second Typical |
| Time Above Liquidus (TAL) |
60 Seconds Nominal
45 to 75 Second Process Window |
| Peak Temperature |
215˚C Nominal
210˚C to 220˚C Process Window |
| Profile Length |
3 ½ to 4 minutes max
from 45˚C to Profile Peak |
| Cool Down |
2.0˚C to 3.0˚C Per Second Typical |
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| STORAGE AND HANDLING |
- Cartridges should be stored tip down.
- Paste can be stored up to two weeks at room temperature.
- To prolong the shelf life of NC676, refrigerate between 5°C~10°C, (41°F~50°F). At this range the shelf life will exceed 9 months.
- NC676 should not be allowed to freeze.
- When refrigerated, solder paste must be allowed to warm up to room temperature.
- Paste must be ≥22˚C, (~66˚F) prior to applying to stencil for processing.
- Working range of NC676 is between 22-32˚C, (~66˚F – 89.5˚F).
- First-In-First-Out (FIFO) inventory management practices should be used with all solder pastes.
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