Solder Paste Analysis & Testing

For Surface Mount Technology (SMT), Printed Circuit Board (PCB) production & assembly, the solder paste printing is an important step. As the solder paste is used to directly form the soldering joint for the component, the quality of solder paste printing directly affects the performance and reliability of the surface mount assembly and integrity. High-quality solder paste printing ensures a quality solder joint and final end-product. Statistical analysis has shown that 60%-90% of soldering defects are directly related to solder paste printing defects.

Reference Documents And Specifications

IEC 61189-5

Test methods for electrical materials, interconnection structures and assemblies –

Part 5: Test methods for printed board assemblies

IEC 61189 is a catalogue of test methods representing methodologies and procedures that can be applied to test printed board assemblies.


IPC-TM-650 Test Method 2.4.35

Solder Paste – Slump Test

Test Method 2.4.25 procedure determines vertical and horizontal slump for solder pastes.


IPC-TM-650 Test Method 2.4.43

Solder Paste—Solder Ball Test

Test Method 2.4.43 is carried out to determine the reflow properties of the solder paste. The ability of the pre-alloyed solder particles in the paste to reflow into a sphere on a non-wettable substrate is determined under defined test conditions.


IPC-TM-650 Test Method 2.4.44

Solder Paste—Tack Test

Test Method 2.4.44 is to determine the ability of a printed pattern of solder paste to retain a probe placed in the solder paste by measuring the force required to separate the probe from the paste. Time between printing and probe placement are progressively increased to simulate variables in a manufacturing process.


IPC-TM-650 Test Method 2.4.45

Solder Paste—Wetting Test

Test Method 2.4.45 determines the ability of a solder paste to wet an oxidized copper surface and to qualitatively examine the amount of spatter of the solder paste during reflow.


IPC-TM-650 Test Method 2.4.46

Spread Test, Liquid or Extracted Solder Flux, Solder Paste and Extracted Cored Wires or Preforms

Test Method 2.4.25 will provide an indication of activity of wave solder fluxes, core solder fluxes, and solder paste.