Polymers have been used extensively in IC packing and other electronic industries due to the insulating, easy processing and cost-saving advantage. As the devices become more complex, the resulting package construction become more complicated too.

Cracking is a typical failure mode in packaging. With the most common type of cracking, de-lamination and eventual fracture occur along the backside of the chip pad and propagate in a radial manner. This failure can be a result of

  1. different in CTE (coefficient of thermal expansion) between the chip and polymer
  2. contamination introduced during mounding process
  3. impurity in polymer

As a result, to design packages with high reliability, a good understanding of the physical properties (e.g. thermo-mechanical behavior) of the polymer in various processes and operational environments is essential.

Regarding polymers, ASMAC are able to find out the following parameters with the appropriate techniques:

Properties:

  1. Material analysis
  2. Thickness determination
  3. CTE (coefficient of thermal expansion)
  4. Tg (glass transition temperature)
  5. Elastic Modulus
  6. Stress and strain relationships
  7. % of filler

Instruments:

  • FT-IR
  • micro-section and SEM
  • TGA
  • TMA
  • DMA
  • DSC

Examples

A. Tg and CTE measurements of Laminate after curing
Analysis Technique: TMA


Figure 28 thermograph of laminate after curing (Tg: 165 °C; CTE 1: 74.6x10-6/ °C; CTE 2: 291.3x10-6/ °C)

B. Time to delamination
Anlaysis Technique: TMA


Figure 29 Thermograph of PWB until showing irreversible delamination.

C. Polymer identification
Analysis technique: FTIR


Figure 30 FTIR spectra of the plastic bottle and the reference.
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  ASMAC can now offer Scanning Acoustic Microscopy (SAM) service. SAM is an idea technique to study subsurface defects and crack propagation in materials.

ASMAC can provide electropolishing and chemical polishing service for metal finishing and metallurgy preparation purposes, including process development and refining for high quality products.