Methods for ultrashort pulse laser processing of optically transparent materials. A method for scribing transparent materials uses ultrashort laser pulses to create multiple scribe features with a single pass of the laser beam across the material, with at least one of the scribe features being formed below the surface of the material. This enables clean breaking of transparent materials at a higher speed than conventional techniques. Slightly modifying the ultrashort pulse laser processing conditions produces sub-surface marks. When properly arranged, these marks are clearly visible with side-illumination and not clearly visible without side-illumination. In addition, a method for welding transparent materials uses ultrashort laser pulses to create a bond through localized heating. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials. The laser is focused near the interface of the materials, generating a high energy fluence at the region to be welded. This minimizes damage to the rest of the material and enables fine weld lines.

Transparent material processing with an ultrashort pulse laser

Various embodiments may be used for laser-based modification of target material of a workpiece while advantageously achieving improvements in processing throughput and/or quality. Embodiments of a method of processing may include focusing and directing laser pulses to a region of the workpiece at a pulse repetition rate sufficiently high so that material is efficiently removed from the region and a quantity of unwanted material within the region, proximate to the region, or both is reduced relative to a quantity obtainable at a lower repetition rate In at least one embodiment, an ultrashort pulse laser system may include at least one of a fiber amplifier or fiber laser. Various embodiments are suitable for at least one of dicing, cutting, scribing, and forming features on or within a semiconductor substrate. Workpiece materials may also include metals, inorganic or organic dielectrics, or any material to be micromachined with femtosecond and/or picosecond pulses, and in some embodiments with pulse widths up to a few nanoseconds.

Laser-based material processing methods and systems

PROBLEM TO BE SOLVED: To provide a dicing method which is less in breaking or cracking on a semiconductor wafer, reduces the futility of a usable area on a semiconductor wafer, and enables the achievement of a high production throughput.SOLUTION: Methods of dicing semiconductor wafers, each having a plurality of integrated circuits mounted thereon are disclosed. The method comprises: a step 302 for forming, on a semiconductor wafer, a mask for covering and protecting the integrated circuits; a step 304 for patterning the mask by femtosecond laser scribing to form a patterned mask with gaps and to expose regions between the integrated circuits on the semiconductor wafer; and a step 306 for etching the semiconductor wafer through the gaps of the patterned mask to cut the wafer into the individual integrated circuits.SELECTED DRAWING: Figure 3

Wafer dicing using femtosecond-based laser and plasma etch

An improved method for singulation of compound electronic devices is presented. Compound electronic devices are manufactured by combining two or more substrates into an assembly containing multiple devices. Presented are methods for singulation of compound electronic devices using laser processing. The methods presented provide fewer defects such as cracking or chipping of the substrates while minimizing the width of the kerf and maintaining system throughput.

Method for laser singulation of chip scale packages on glass substrates

A combination of specific laser pulse durations and repetition rates are incorporated into a semiconductor wafer laser scribing/dicing process. The disclosed combination can reduce factors that contribute to thermal effects, explosive melting and evaporation, and laser/plasma interactions, thereby reducing problems with microcracks, delamination, and particles that can affect semiconductor die yields and reliability.

Laser ablation method

The present invention relates to the apparatus, system and method for dicing of semiconductor wafers using an ultrafast laser pulse of femtosecond and picosecond pulse widths directly from the ultrafast laser oscillator without an amplifier. Thin and ultrathin semiconductor wafers below 250 micrometer thickness, are diced using diode pumped, solid state mode locked ultrafast laser pulses from oscillator without amplification. The invention disclosed has means to avoid/reduce the cumulative heating effect and to avoid machine quality degrading in multi shot ablation. Also the disclosed invention provides means to change the polarization state of the laser beam to reduce the focused spot size, and improve the machining efficiency and quality. The disclosed invention provides a cost effective and stable system for high volume manufacturing applications. An ultrafast laser oscillator can be a called as femtosecond laser oscillator or a picosecond laser oscillator depending on the pulse width of the laser beam generated.

Tan Deshi

Papers

Method and apparatus for dicing of thin and ultra thin semiconductor wafer using ultrafast pulse laser