Christopher Associates has introduced the S3X-BF70M and 200N series wafer bumping pastes exhibiting a high definition over time and at elevated temperatures. There are various ways to form solder deposits on wafers. Printing solder paste and reflowing into an array of bumps is both quick and easy. Almost 70% of the short runs and prototypes are eligible for stenciling solder paste to form the array of bumps. The two series are the standard in wafer bumping processes across most Asian companies.
For ordinary 250μm bump sizes, the S3X-BF70M series is suitable. The paste offers high cleaning performance in a SAC305 powder with a 20 to 38μm diameter. For super fine 100μm bump sizes, the S3X-BF200M series with a SAC305 powder and 5 to 20μm diameter is available.
