Holographic laser material processing

Spatial light modulator and holograms

By controlling the phase spatially, it becomes possible to control light diffraction and interference phenomena, and to form an arbitrary light intensity distribution with high light utilization efficiency. The phase distribution for generating such an arbitrary light intensity distribution with LCOS-SLM can be calculated. This is called Computer Generated Hologram (CGH) and can be calculated easily by a computer. Compared to a general projector that adjusts the light intensity by transmittance of light, the holographic beam forming technology using CGH is a technique that skillfully uses the interference effect of light without light loss. This technology is particularly effective for laser processing with strong incident light intensity. In general projectors, light is often converted into heat where light is blocked, which may directly affect the lifetime of the processing machine. In holographic beam shaping, this thermal conversion effect is small, high-intensity light can be used. In addition, since the light collected by the lens can be split into multiple beams, high-precision and high-throughput processing can be realized, and construction of a system that qualitatively changes productivity in the manufacturing industry is also expected.

Fully automatic laser marking to innovate production line

By capturing the position of the red laser with a high-speed camera and displaying the hologram calculated based on the position information on the spatial light modulator, the pattern generated by the green laser can be displayed on the red laser.
Development of a system that can capture lasers at appropriate directions and positions at high speed by extracting feature quantities and applying feedback is expected, particularly when processing objects with curved surfaces flow through the production line in various directions.

Irradiation of marking laser to objects on assembly line

Combination of LCOS-SLM technology and high-speed sensing  ~Laser tracking~

Stealth dicing and towards high precision

The Stealth Dicing ™ process is a dicing method that uses a pulsed laser to perform high-quality division by processing the inside of the wafer. In semiconductor manufacturing, wafers have become larger in size, but their thickness has become very thin. How many devices can be cut from a single wafer without loss, or how can a high-performance integrated circuit be cut without damaging the dicing process, the smaller the end product becomes, the higher the performance of this method will be required. In this technology, it is necessary to focus the laser beam inside the wafer with high accuracy in order to extend the crack. However, since silicon, which is a general wafer material, has a high refractive index, if there is an interface between the air and the silicon material during focusing, the laser focusing characteristics deteriorate due to spherical aberration will be occurred. Therefore, by installing LCOS-SLM, it becomes possible to correct spherical aberration, and the same correction can be realized even if the wafer material changes.


  1. E. Ohmura et al., "Internal modified-layer formation mechanism into silicon with nanosecond laser", Journal of Achievements in Materials and Manufacturing Engineering 17, 381(2006).
  2. M. Kumagai et al., "Advanced Dicing Technology for Semiconductor Wafer - Stealth Dicing", IEEE Transactions on Semiconductor Manufacturing 20, 259(2007).
  3. E. Ohmura et al., "Analysis of Processing Mechanism in Stealth Dicing for Ultra Thin Silicon Wafer", Journal of Advanced Mechanical System Design, Systems, and Manufacturing 2(4), 540(2008).
  4. Yu Takiguchi, Taro Ando, Yoshiyuki Ohtake, Takashi Inoue, Haruyoshi Toyoda, “Effects of dielectric planar interface on tight focusing coherent beam: direct comparison between observations and vectorial calculation of lateral focal patterns”, Journal of the Optical Society of America A 12/2013; 30(12):2605-10.
  5. Yu Takiguchi, Masaki Oyaizu, Makoto Nakano, Takashi Inoue, Haruyoshi Toyoda, "Suppression of backside damage in nanosecond internal-focusing pulse laser dicing with wavefront modulation," Optical Engineering 56(7), 077109 (2017)

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