Advanced laser machining technology for silicon / composite materials/ ceramic / glass

When products are getting smaller, thinner, l ighter and more compact, laser micro machining for silicon, glass, ceramic, flex circuits, composite materials, thin film, , metal, and plastic is commonly used to meet challenges for micro holes, via, grooving, trenching, cutting, marking and direct writing as it is precise, fast, flexible, non destructive. However, laser micro machining is a sophisticated process which combines laser source, optical beam path design, precision motion control, vision alignment, and laser pulse control technologies . But the fact is that most of laser system companies do not develop their own core technologies like motion control and image processing, which makes laser micro machining results difficult to satisfy customers expectations.

At SSI, we have been involved in developing the core technologies for advanced packaging process for more than a decade including most advanced motion control, imaging processing, vision algorithms, piezo behavior control and sub-micron system design. To meet laser micro machining challenge, SSI developed the unique capabilities for ultra short laser pulse control and in-house optical path design. SSI laser micro machining solution unlike other laser equipment companies owns the following unique core technologies.

1. Extreme high precision multi-axis motion and pulse energy control integrated system

Embedded bottom motion control software with high speed close up feedback for laser pulse energy control and distribution at the right position and right moment to optimize the laser processing result with minimum HAZ (heat affected zone) effect.

2. Extreme precision mechanism and platform design via software simulation, which can ensure ultrahigh frequency vibration response in 10-3 sec as well as machine stability due to stress and temperature variation.

3. Exclusive CxVis Vision system (Vision system is one of the most important factor affecting of laser micro machining result as vision system is guiding laser beam to the exact position for laser processing. Laser micro machining is talking  about few micron accuracy. CxVis is a state of the art vision software exclusively developed by SSI, which offers many unique features including *alignment on fly* for high speed high precision laser process automation and height detection on fly for 3D fabrication. The total ownership of original bottom coding allows SSI customize software and algorithms for specific applications as necessary.

4. Advanced optical beam path design Optical beam path is an essential part of laser micro machining system. SSI has in-house optical path design capabilities.

The following are two main optical path architectures commonly used for most of applications:

a. Direct Beam Dot to dot Technology with energy equalization

    Direct beam architecture has the advanatge of high acccuracy and consistency and is suitable for for large working areas, smaller beam size down to 1um and deep hole applications. constant frequency pulse has beam overlapping issues because motion speed is changing at corners due to deceleration and acceleration, which cause serious HAZ concerns. With SSI dot to dot software feature, laser pulse frequency synchronizes with the motion speed, which eliminates laser beam overlapping problems. Laser beam response delay can be controlled within 5ns up to 1 mega.

    However, even with dot to dot feature, laser energy variations caused by laser pulse frequency also needs to be resolved because laser pulse energy will normally increase when laser pulse frequency is reduced. SSI direct beam technology integrates dot to dot and constant laser pulse energy control simultaneously, which completely avoid problems caused either by motion speed or pulse energy variations. When dot to dot frequency control feature is activated, SSI laser control system will simultaneously activate the laser beam energy control feature to provide constant laser beam energy within ±1% tolerance.

b. Galvo Scanning Architecture v
    Galvo scanning system, on the other hand , has the advantage of higher speed, but not
    as precise as direct beam system. Optical path system normally is decided depending
    on applications. However, SSI galvo scanning system is an advanced galvo scanning
    system, which integrates 2D calibration software capabilities for substrate deformation
    compensation like warpage as well as controlling Z axis control on the gantry and the
    height of the lens on the scanning Z axis to compensate substrate to Improve overall
    system precision.