Scanning & Adjustment with DENSO and Comet

CHALLENGE 

Without microchips and their semiconductors, our world literally would come to a standstill: Serving as control elements, they can be found in cars, consumer electronics as well as in high-tech systems across industries. Central to the production of semiconductors are wafers. Measuring only millimeters and usually circular in shape, it’s the silicon-based wafers where microelectronic circuits are being generated. Important processes such as the deposition, modification and structuring of various materials on wafers are implemented by using plasma technology. At the same time, the structures of microchips are becoming increasingly smaller and more complex - a highly dynamic trend towards miniaturization also setting the pace for the development of subsystems for wafer production.

These are the requirements placed on the equipment crucial for plasma generation: The radio frequency (RF) generator, whose energy is used to generate plasma. Without these high-precision RF generators, there is no stable plasma for wafer processing - and therefore no semiconductors. Until now, the assembly, adjustment, testing and final inspection of these generators have been carried out manually, with all the inherent, potential risks and inaccuracies for subsequent operations.

SOLUTION 

An important player in this market is the high-tech company Comet, founded in Switzerland in 1948, which focuses on the inspection of plasma and X-ray technologies. Today, the company operates at 12 locations around the world and has a total of more than 1500 employees. 

Comet develops first-class high-tech components and systems for the semiconductor and electronics market, the aviation and automotive industries and security inspections. This portfolio was rounded off in 2022 with Synertia®, a high-frequency platform for real-time control of plasma processes. The platform offers a number of advantages, including high repeatability, multi-level pulsing and high-speed communications. This responsiveness provides actionable data for process optimization, thereby enabling more complex plasma applications than ever before. At the core of the system is the RF generator Synertia® RFG, which is assembled and adjusted in a semi-automated manufacturing line at the company’s Aachen site in Germany. The Synertia® RFG is available in different frequencies. Depending on the generator’s performance, it is either equipped with water-based or air-based cooling technology.

A key stage in this manufacturing process is an adjustment and testing cell with a DENSO Robotics HS-045 A1 SCARA robot at its center. The main task of the cell is to check and adjust the precise installation of a measuring device mounted on the generator. As each generator is being assembled manually step-by-step as a single piece, minuscule deviations may occur during the measuring module’s mounting. However, for the generator to be able to later operate precisely, the exact mounting ultimately is affecting the stability of the plasma generation. Adding to this challenge is the fact that the Synertia® RFG comes in different model types.

In the production line, the generators are assembled step by step in a single piece until they arrive at the semi-automated cell with the HS-045 A1. The transport platform is manually docked into the cell. The device type is then recorded by a barcode scanner; all data relevant to the assembly process, such as the specific measuring device position and generator-specific setting parameters, are uploaded dynamically. Once this process has been completed, the robot will start working. The robot is mounted on the cell’s ceiling and is equipped with laser sensors and a vision system.

The scanning and testing process is the same for all generator types. However, the position of the device module varies depending on the generator type, which is first downloaded from the database. In order to subsequently compensate for tolerances in assembly and production, the robot, using the vision system, starts with determining the exact positioning of the test module. This is done by detecting the position of several screws (1.8 mm long and 0.3 mm in diameter) used to attach the test module to the generator. The main task of the robot is to adjust the test module’s exact positioning on the generator: On average, this process takes 8 - 10 minutes in total, depending on the type.

"When we set up the production line, it became clear that a SCARA robot was the most flexible solution for addressing these variable requirements," explains Mark Lautermann, Automation Engineer at Comet in Aachen. “Using DENSO Robotics was a natural choice for us, as we have had good experiences with the company’s other robot models. We were looking for a high-precision flexible in its movements and easy to program."

In total, Comet is using five DENSO robots. Primarily designed for high-speed industrial applications, the four-axis SCARA robot has an arm length of 450 (225 + 225) mm, a payload of up to 5 kg and a cycle time of 0.20 seconds, thereby offering the perfect combination of speed, precision and payload. 

"In the end, the decisive factors were the robot's high, industry-standard repeatability of ±0.02 mm and the compact and uncomplicated control system. The ability to program the robot with high-level languages such as LabVIEW and Python means that the system can be optimally integrated into higher-level database-driven and QM-capable operations.“

ADVANTAGES 

A major advantage of the robot-based cell is data monitoring serving as the basis for a highly valuable quality management. Throughout the entire process, all data are stored in a database using SPC (Statistical Process Control) and compared with the limit values, i.e. all fluctuations are recorded - a fully database-driven production process. Thanks to this and the complete integration of the robot-based adjustment cell, the entire generator production process offers a significantly higher level of product quality and safety. 

Thanks to their performance, compactness and high positioning accuracy, the DENSO SCARA robots are a crucial component for a state-of-the-art wafer production.