Semiconductor industry – dedicated to permanent technical progress

The semiconductor industry is predicted to grow at a healthy rate of 6% to 8% over the next years. Technical progress in the semiconductor industry continues to evolve with each iteration; almost every new consumer electronics product is smaller, lighter, smarter and more energy efficient than its respective predecessor.

The proliferation of IoT (Internet of things), machine learning (ML), and artificial intelligence (AI), as well as the advancement of autonomous driving, for example, offer new opportunities & sales markets and are driving the high-end application segment in the consumer electronics and automotive industries. Factors such as population growth and increasing urbanization, as well as pandemic effects – such as the rising trend of working on the go or from home and the boom in online shopping – are creating massive global demand for consumer electronics devices such as smartphones and smart devices.

Litho Black in semiconductors

Amplification of the sensor signal through stray light optimization

Acktar’s super-thin, light-absorbing coating products are suitable for wafer-level optics and miniature optics. Applying Acktar’s deep black materials to wafers – either to active areas of the product or to non-active areas – provides controlled stray light suppression to enhance the sensor signal and prevent optical crosstalk. ACKTAR products have very low particle contamination and meet very stringent cleanroom requirements. They have high adhesion to various substrates, such as metals, polymers and ceramics, including various wafers, such as glass, silicon, sapphire, lithium tantalate, indium phosphide or even dielectric insulating layers, such as silicon oxide and silicon nitride.

Highly absorbing properties over the entire spectral range EUV – VIS – IR

Acktar’s deep black materials for wafer-level optics and semiconductor devices exhibit highly absorbing properties over the entire EUV- VIS- IR spectral range. Acktar Litho-Black™ is the predestined coating product in our portfolio for micro-level applications. In as little as 0.8-3 µm, it enables the blocking of stray light from extreme ultraviolet for demanding applications, through visible and infrared wavelength bands. Acktar Litho-Black™ provides a cost-effective solution for improving the design and efficiency of devices such as CMOS sensors, DMD/DLP, CCD and MEMS. Direct deposition of the thin deep black layer is integrated into the optical chip as part of the design.

Characteristics of Acktar Litho-Black™

  • very thin coating
  • consists exclusively of non-ferrous metals and oxides
  • does not contain organic materials
  • extremely low outgassing
  • fully compatible with etching and lift-off processes
  • vacuum, cryogenic and clean room compatible


ACKTAR deep black coating in the camera lens

Improving the contrast of the smartphone camera

Acktar Litho-Black™ is used, for example, on camera lenses of smartphones and mobile phones. The lens barrels made of molded polycarbonate were coated with Acktar Litho-Black™. Since these are only a few millimeters in diameter, the light-absorbing coating must be particularly thin and perform well. The result of stray light optimization with Acktar Litho-Black™ is an improvement in the optical performance of miniature cameras in smartphones. By capturing stray light in the VIS wavelength range, ghosting effects are eliminated and contrast is significantly improved.

Improvement of the signal-to-noise ratio of an IR detector

The Acktar Litho-Black™ coating has also been applied in thermal IR detectors. These pyroelectric, wafer-level sensors serve, among other things, as motion and presence detectors for intelligent air-conditioning systems. They detect surface temperatures and the exact location of people and animals in the room and convert their thermal radiation into an electrical signal. This signal is in turn processed into a signal that can be evaluated. To optimize coverage of the field surface whose temperature is being monitored, the Acktar Litho-Black™ coating was used. It increased the energy absorption of the sensor and improved the signal-to-noise ratio by eliminating over 99% of stray light.

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