Novel HRL1 Low Temp Alloy Pb-Free & Zero Halogen Ultra-Low Warpage

ALPHA® OM-550
Low Temperature No-Clean Solder Paste

ALPHA® OM-550 is a revolutionary no-clean, low-temperature, lead-free solder paste paired with HRL1 alloy, specifically engineered for temperature-sensitive substrates, components, and high-warpage package assemblies. It enables peak reflow at ~175°C, reducing warpage by up to 99% while delivering superior drop shock and thermal cycle reliability.

Product Overview

ALPHA® OM-550 is a lead-free, zero-halogen, no-clean, low-temperature solder paste formulated with the novel HRL1 non-eutectic Bi-Sn alloy. Compared to traditional low-temperature alloys, the HRL1 alloy delivers vastly superior drop shock resistance and thermal cycling reliability performance.

This carefully balanced flux and alloy system exhibits excellent printing characteristics and modern solder paste rheology, minimizing Non-Wet-Open (NWO) and Head-in-Pillow (HIP) defects during low-temperature reflow. With peak reflow temperatures as low as ~175°C, it helps mitigate package and board warpage by up to 99%.

Note: All components used with ALPHA OM-550 must be lead-free to eliminate the formation of tin/lead/bismuth intermetallic which has a melting point under 100 ºC.

ALPHA® OM-550 Solder Paste Product Image

Revolutionizing Low Temperature Solder Reliability

ALPHA OM-550 HRL1 is a high reliability, low temperature solder paste designed to increase production yield and reduce component warpage. The ALPHA HRL1 alloy has a melting point significantly lower than SAC 305 and was designed to exhibit improved drop shock and thermal cycling performance. A minimum peak temperature of only 185°C vs 245°C reduces energy consumption in the SMT process.

Improved Reliability

ALPHA OM-550 HRL1 mechanical reliability is comparable to SAC305 and significantly improved over other low temperature solders.
Drop shock performance in SAC mixed alloy joints increased by 100% compared to other SnBi alloys.
Thermal cycling reliability in SAC mixed alloy joints improved by 20%.
HRL1 alloy shows best compatibility with SAC alloy vs. other low temperature SnBi alloys.

Note: The PDF charts for "Drop Shock Results" and "Peak Reflow Window" are incorporated in the detailed technical specifications below.

PERFORMANCE SUMMARY

PROCESS BENEFITS PROPERTIES PERFORMANCE CAPABILITIES
Print Process Window Fine Feature Print Definition 180 micron using 4 mil stencil
250 micron using 5 mil stencil
Tack/Stencil Life Over 12 hours stencil life
Print Speed Range 25–150mm/s (1–6 in.sec)
Reflow Process Yield Reflow Environment Air and Nitrogen
Resistance to Voids Meets IPC 7095 Class III Requirements
Random Solder Balls Passes in preferred category
Head-in-Pillow High Resistance to Head-in-Pillow Defects
Non Wet Open (NWO) High Resistance to NWO Defects
Residue Profile Pin Testable
Coalescence Coalesces down to 170 microns
Flux Residue Cosmetics Clear
Electrical Reliability SIR IPC SIR J-STD-004B and Bellcore SIR
J-STD-004B Classification ROL0 (Halide-Free)
Environmental Halogen Content Zero-Halogen

REDUCTION IN SHEAR STRENGTH % AFTER THERMAL CYCLING

NO.
CYCLES		 CVP-390
SAC305 T4		 CVP-390
SAC305 T5		 OM-535
SBX02 T4		 OM-550
HRL1 T4		 OM-550
HRL1 T5
500 43.3%45.3%3.8%5.4%13.5%
1000 67.6%71.3%32.3%16.2%25.6%
1500 74.1%78.7%62.0%34.7%44.4%
2000 80.0%84.6%68.4%50.1%52.4%
2500 80.1%82.8%76.5%58.7%54.5%

ALPHA OM-550 HRL1 exhibits the lowest drop in shear strength after thermal cycling. The HRL1 alloy loses less shear strength than SAC305 for both mixed alloy joints and joints with HRL1 alone.

Product Features

Product Features Detail

Low reflow peak temperature: ~175 °C (~185 to 195 °C for mixed alloy process)

Reduction of warpage: up to 99% (component and board/substrate) vs SAC process

Long Stencil Life: 12 Hours with continuous printing

Good voiding performance: on various packages (BGA, MLF, DPAK, LGA)

ALPHA OM-550 HRL1 Features & Specifications List

ALPHA OM-550 HRL1 Features

  • Low reflow peak temperature ~175°C: (~185°C – 195°C for mixed alloy process)
  • Reduction of warpage up to 99%: (component and board/substrate) vs SAC process
  • Excellent NWO Performance
  • Excellent HIP Performance
  • Improves BGA mechanical reliability compared to other low-temp alloys
  • Fine Feature Printing/Reflow Capable
  • Long Stencil Life - 12 Hours with continuous printing
  • Less residue spread
  • Good voiding performance on various packages (BGA, MLF, DPAK, LGA)
  • Reflowable in air or nitrogen
  • Provides efficiencies in both energy and cost

ALPHA OM-550 HRL1 Specifications

Alloys HRL1 alloy
Powder size Type 5
Packaging sizes 500 gram jar
Lead-free Lead-free
Zero-Halogen Zero-Halogen
View Detailed Product Parameters

Product Information

Alloys: HRL1 Alloy (Non-eutectic Bismuth-Tin Alloy)
Powder Sizes: Type 4 and Type 5 (Type 5 is standard for Part 246836-1998)
Packaging: 500-gram jars; 6" and 12" cartridges; 30cc syringes
Lead Free: RoHS Directive EU/2015/863; amending Annex II of 2011/65/EU
Halogen Content: Zero-Halogen (no halogen intentionally added)

Technical Specifications

Category Results Procedures/Remarks
Chemical Properties
Activity LevelROL0IPC J-STD-004B
Halide ContentPass (Halide-free)IPC J-STD-004B
Fluoride TestPassIPC J-STD-004B
Halogen TestPassZero-Halogen
Silver Chromate TestPassIPC J-STD-004B
JIS-Z-3197-1999 8.1.4.2.3
Copper Mirror TestPassIPC J-STD-004B
JIS-Z-3197-1999 8.4.2
Copper Corrosion TestPassIPC J-STD-004B
JIS-Z-3197-1999 8.4.1
Electrical Properties
SIR (7 days, 40 °C/90% RH, 12V bias)PassIPC-TM-650 2.6.3.7 (J-STD-004B)
Bellcore SIRPassBellcore GR-78 Core Issue 1, Sept 1997 (Chapter 13)
ElectromigrationPassIPC-TM-650 (2.6.14.1), according to J-STD-004B standard
Bellcore ElectromigrationPassBellcore GR78-CORE (Pass criteria: Final > Initial/10)
Physical Properties
ColorClear, colorless flux residue-
Tack Force vs. HumidityPassJIS-Z-3284-3:2014, 4.5
IPC J-STD-005
SolderballExcellentIPC J-STD-005
Spread>80%JIS-Z-3198-3
Wetting TimePassRhesca Test, Zero cross time T0
Stencil Life>12 hours50% RH, 23 °C (74 °F)
Cold/Print SlumpNo bridgingJIS-Z-3284-3:2014, 4.3
IPC J-STD-005
Hot SlumpNo bridgingJIS-Z-3284-3:2014, 4.4
IPC J-STD-005
Dryness Test (Talc)PassJIS-Z-3197-1999 8.5.1

Processing Guidelines

Storage & Handling Printing Reflow (See Figure #1) Cleaning
  • Refrigerate to guarantee stability at 0-10 °C (32-50 °F). Shelf life of Type 4 is 6 months; Type 5 is 3 months under these conditions.
  • Paste can be stored for 2 weeks at room temperature up to 25 °C (77 °F) prior to use.
  • When refrigerated, allow paste container to warm to room temperature for up to 4 hours. Paste must be ≥19 °C (66 °F) before processing. Verify paste temperature with a thermometer to ensure paste is 19 °C (66 °F) or greater before set-up.
  • Paste can be manually stirred before use. A rotating/centrifugal force mixing operation is not required. If a rotating/centrifugal force mixing device is used, 30-60 seconds at 300 RPM is adequate.
  • Do not remove worked paste from stencil and mix with unused paste in jar. This will alter rheology of unused paste.
  • These are starting recommendations and all process settings should be reviewed independently.

Stencil: Recommended ALPHA CUT or ALPHA FORM stencils @ 0.050mm to 0.150 mm (4-6 mil) thick for 0.4 to 0.5 mm (0.016" or 0.020") pitch.

Stencil design is subject to many process variables. Contact your local Alpha stencil site for advice.

Squeegee: Metal (recommended)

Pressure: 1.5 lb/in (Alpha test result)

Speed: 100 mm/sec (Alpha test result)

Paste Roll Diameter: 1.5-2.0 cm, make additions when roll reaches 1cm (0.4") diameter (min.). Max roll size depends on blade type.

Stencil Release Speed: Up to 7 mm/sec

Lift Height: 8-14mm (0.31-0.55")

Atmosphere: Clean-dry air or nitrogen atmosphere is recommended.

Profile (HRL1 Alloy): The following reflow profile has been proven to yield good joints, though other profiles may also work. *Note 1 & 2

Ramp Rate: 40-100 °C, 1-3 °C/s

Soak: 100-120 °C, 60-100s

Time Above Liquidus: >151 °C, 80-120s

Peak Temp: 185 - 195 °C

Aperture volume/BGA sphere volume ratio: 0.4-0.6 (recommended)

ALPHA OM-550 residue is designed to remain on the board after reflow.

Misprints and stencil cleaning may be done with ALPHA SM-110E, ALPHA SM-440 or ALPHA BC-2200 cleaners.

Reflow Profile Recommendations

OM-550 Reflow Profile

Recommended Reflow Profile: Mixed SAC/HRL1 Joint and HRL1 (Solder Only) Joint

*Note 1: Lower peak reflow temperatures require an adjusted/extended dwell above liquidus to form proper joints. Fine-tuning based on PCB design is required for optimum performance. The profile above represents a single exposure profile. For assemblies requiring multiple reflow exposures, please contact your local Alpha representative.

**Note 2: Peak reflow temperatures of 185°C–195°C are recommended for mixed SAC/HRL1 joints.

The ratio of solder paste volume to BGA sphere volume recommended for this profile is 0.4-0.6.

OM-550 Straight Ramp Profile

***Note 3: Straight ramp profile is only for HRL1 solder only joints.

Product Documentation

ALPHA® OM-550 Solder Paste TDS

Simplified Chinese

ALPHA® OM-550 Solder Paste TDS

English

ALPHA® OM-550 Brochure

Simplified Chinese

ALPHA® OM-550 brochure

English