Dow Electronic Materials
SOLDERON™ BP TS 6000 Tin-Silver Plating Chemistry for
Fine-Pitch Solder - Bumping Applications

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SOLDERON™ BP TS 6000 Tin-Silver plating chemistry is a high-performance lead-free alternative optimized for today's fine-pitch solder bump plating applications such as Cu pillar and micro-bumps used in 2.5D and 3D IC packaging technologies. This next-generation formulation delivers industry-leading plating rates and maximum process flexibility for flip chip packages and interconnects (Figure 1). The new chemistry features enhanced plating performance, bath stability and ease-of-use, thereby enabling the industry's widest process window with the most robust process flexibility and a competitive cost of ownership (COO).

This single formulation is capable of plating speeds ranging from 2 to 9+ µm/min. The tunable nature of the Ag composition in this formulation makes it suitable for a number of applications and eliminates the need to change the chemistry to address different processing requirements. The chemistry is robust enough for both bumping and capping of a wide range of patterned wafers and it is not restricted for use with specific photoresists (Figure 2). It exhibits post-reflow with-in die (WID) bump thickness uniformity of <5% over a wide range of wafer types, which demonstrates its suitability for high-volume manufacturing (Figure 3). Additionally, it is macro- and micro-void free after reflow for improved yields and reliability (Figures 4 and 5).

SOLDERON BP TS 6000 Tin-Silver plating bath has proven to be both electrolytically and thermally stable. Offering an electrolytic bathlife of > 100 Ah/L and a ≥6-month pot life, it is compatible with in-line metrology processes, for superior ease-of-use.

Process Versatility

Examples of product’s process window for a range of solder bump applications

Figure 1.
Examples of SOLDERON BP TS 6000 Tin-Silver's wide process
window over a range of applications, process conditions and plating rates.

Photoresist Compatibility

Picture of void-free performance with both dry-film and liquid photoresist

Figure 2.
SOLDERON BP TS 6000 Tin-Silver exhibits consistent,
void-free performance with both dry-film and liquid photoresist.

Thickness Uniformity: Within Die (WID) and Within Wafer (WIW)

Chart showing thickness uniformity of SOLDERON plating bath

  • WID Uniformity <5% from 6-10 ASD
  • WIW Uniformity <10% from 6-10 ASD

Figure 3.
WID and WIW uniformity of SOLDERON BP TS 6000 Tin-Silver
demonstrates its suitability for high-volume manufacturing.

Morphology, Voiding Performance

Pictures of improved uniformity and smoother surface morphology after SOLDERON plating bath

Figure 4.
SOLDERON BP TS 6000 Tin-Silver offers improved uniformity and smoother surface
morphology in addition to a smooth, void-free interface when used together with Dow's
and other leading copper (Cu) pillar formulations.

Intermetallic Compound

Pictures of smooth interface after SOLDERON plating bath in Cu pillar capping applications

Figure 5.
In Cu pillar capping applications, SOLDERON BP TS 6000 Tin-Silver forms
a smooth, micro-void free interface post reflow.