- Grooving USP Matrix is used when Low Burr & High DIE strength are a must.
- The Ultra Short Pulse technology assures that the material in the street is more evaporated instead of melted.
- Less melt on top of the wafer results in low Burr. Mostly < 2 um.
- Less melt on the sidewall (recast) result in higher Die strength.
- Like Grooving with a nanosecond laser, the matrix process allows to achieve the required depth in a single pass resulting in a higher WPH (Wafer per Hour).
- The Grooving USP Matrix process is a patented process.
High die-strength, Low burr & Crack free
As the Si substrate gets thinner the die strength of the devices after singulation becomes more important.
It is generally known that a nano second UV laser grooving process does not provide a sufficient die strength (typical 250 – 300MPa). A general request from the industry is to achieve a die strength value above 700MPa.
A second quality criteria is the burr height on the edge of the device after separation. More advanced packing is moving to (micro) bump die interconnect rather than wire bond. A UV nano second laser grooving process is not able to generate burr below 2um. These are some of the key quality improvements which the industry is looking for apart from no chipping and delamination in the adjacent active structures to the groove and a smooth perfect U-shape profile.
All these requirements can be addressed when moving towards a shorter pulse duration regime. ASMPT has developed a laser grooving technology based on a Ultra Short Pulse (USP) femto second laser which uses its patented multi beam matrix grooving technology. In various applications such as Memory, logic and driver IC’s the process parameters have been optimized to achieve the above-mentioned quality criteria.