PHOSPACK performs die attach on Glass and Silicon Interposers. Semiconductor chips are bonded on the surface(s) or into cavities of the interposer. This process is critical not only for structural attachments but also for establishing an efficient thermal pathway needed by heat flows to be dissipated during die operations.

Structural stability withstanding extreme thermal cycling, mechanical stress, and vibrational forces, especially for quantum photonic packaging applications.

Thermal Management: Good thermal conductivity is crucial for high-power devices, maintaining optimal operating temperatures and ensuring device longevity.

Electrical Performance: In some designs, the die attach material can play a role in electrical grounding or shielding, influencing the overall electrical performance of the final package

Die Attach Process

Die Preparation: Once the wafer is diced into individual chips, dies must be cleaned and inspected to remove any contaminants. Surface preparation is essential to ensure proper adhesion.

Dispensing:

A precise amount of die attach material (adhesive or solder paste) is dispensed onto the substrate or leadframe. Automated equipment ensures consistency and control over the volume.

Material Options:

Adhesives (Epoxy): Often used when mechanical integrity is the priority. They can be formulated with fillers (like silver) to boost thermal conductivity.

Solder or Metal-Based Materials:

Preferred for high thermal conductivity applications. Examples include traditional solder or emerging processes like sintered silver bonding.

Die Placement:

Using pick-and-place machinery, the die is accurately positioned over the dispensed material. Precision here is key—misalignment can impact both heat flow and electrical performance

Bonding (Curing/Reflow):

Adhesives might require a high-temperature cure (thermal or UV) where the material hardens to solidify the bond.

Solder-based processes involve a reflow step where the material melts, wets the surfaces, and then solidifies upon cooling

Inspection and Quality Control,

After bonding, various techniques such as X-ray imaging, shear testing, or metrology measurements are used to verify the bond-line thickness, alignment, and overall quality.

PHOSPACK performs wire bonding on Glass and Silicon Interposers to create electrical connections between semiconductor chips and substrates.

Ball Bonding : (thermosonic method and deep-access) using 1.0mil/25um up to 2.0mil/50um Au wire diameters

Wedge Bonding: (ultrasonic method and deep-access) using especially Aluminum wires

PHOSPACK performs Flip-Chip on Glass and Silicon Interposers to improve electrical connections (between semiconductor chips and substrates) and high integration (enabling direct chip mounts on interposers. It refers to semiconductor chips bonding directly on interposers using techniques such as:

  • Anisotropic Conductive Film (ACF)
  • Under Bump Metallization (UBM) by creating a thin metal layer stack between the chip pads and solder bumps
  • Gold Stud Bumps by creating small gold hemispherical protrusions on contact pads of semiconductor chips. A modified gold ball bonding process is used to create Au stud bumps. Chips are furtherly transferred on interposers and thermocompressed in position.