Success story: ARRI Cine Technik - highest quality with internal wafer inspection

ARRI – Excellence in Cinematic Cameras

For over 100 years, the name ARRI has been firmly linked with the motion picture business. ARRI has developed cameras, lighting, accessories and solutions around film production since its founding in 1917. When the film business faced one of its most significant changes – the introduction of digital cameras – ARRI was ready with its ALEXA series, offering high-end digital cameras to its customers. To provide such high-quality cameras, ARRI controls every aspect of the production process, especially the image sensor, the core component of every camera. As a result, ARRI develops its own image sensors optimized for the film industries specific requirements, including highest sensitivity and an extensive dynamic range. The electronics and housing are also designed to the highest quality.

ACCRETECH enables sophisticated testing procedure

When introducing a new sensor generation, ARRI decided to do the final quality check on wafer level in-house. Their idea was to increase the quality of the selection method, saving money in the long turn and being more flexible with future sensor generations. ARRI was therefore in need of a wafer-prober and approached ACCRETECH. The ACCRETECH application team had already gained much experience in automated wafer-handling from projects at large chip production facilities, and they were used to integrating their machines into the customers’ production environment. Both factors made ACCRETECH a very good choice for ARRI.
During the project, ACCRETECH supplied the knowledge and quality of the wafer probing device so ARRI could implement their quality check on wafer level almost as accurately as if the sensor would have been assembled into a final camera.

Tilt function for contacting large sensors

One big challenge in setting up the ARRI inspection process was the size of the image sensors. With the ALEXA Mini LF camera series, ARRI offers a solution for large-format film productions. But this also requires a large image sensor: 36.70 mm x 25.54 mm with 4448 x 3096 pixels.
The problem: Due to the size of the image sensor, small tilt angles between the wafer and the Probe Card lead to significant differences in distance between both ends of the chip. While one side is barely in contact, on the other side, the needles are bending and potentially destroying the contacting pads of the sensor. To avoid potential destruction of the sensor during the testing, ACCRETECH developed the Head Stage Tilt Unit (Probe Card Tilt Unit), which measures the parallelism of the wafer and Probe Card with high accuracy and adjusts the angle of the Probe Card accordingly. This tilt function ensures a highly uniform contact of all pads with no abrasion or damage to the sensor.
Additionally, due to the lower forces on the needles, the durability of the Probe Card is increased. While in similar testing environments, the Probe Card needs to be refurbished after thousands of measurements, the Probe Card at ARRI is running for more than the expected lifetime. This improves the reliability of the testing equipment and reduces its maintenance costs.

Ready for future chip generations

With their internal equipment, ARRI invested in an inspection procedure tailored to their individual requirement. Consequently they now receive the optimum results. “When we designed the inspection tool, we expected to receive a ballpark number for the quality,” says Christoph Chalfin, Process Engineer at ARRI. “We were surprised that we received almost the same results for the sensors as in the finally mounted camera system. The best situation for an initial quality test.” ARRI’s initial setup has run highly reliably for over 7 years without any unplanned interruption, and has tested thousands of image sensors since its introduction. This helped ARRI significantly reduce the re-work necessary during their camera production and now provides valuable information when analyzing cameras.
Additionally, the in-house testing equipment now offers ARRI the flexibility to adapt the inspection procedure to new sensor generations. For a new image sensor, only a new Probe Card is necessary. “With each new generation, the investment pays off,” says Mr. Chalfin. “With our inspection tool, we now have a comfortable way to ensure a reliable 100% quality check. This helps provide the best quality image sensors for our existing and new generations of ARRI digital cameras.”

Contact:

ACCRETECH (Europe) GmbH
Peter Neundorfer
Landsberger Straße 396
81241 Munich
Germany
Phone +49 89 250064200

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Success story: ARRI Cine Technik – Highest quality with an internal wafer inspection

ARRI Cine Technik – Highest quality with an internal wafer inspection

ARRI – Excellence in Cinematic Cameras

ACCRETECH enables sophisticated testing procedure

Tilt function for contacting large sensors

Ready for future chip generations