08/28/2018

Part 1/5: Hybrid metrology for fast and reliable determination of inaccessible parameters

Semiconductors, MST/MEMS/Nano, Sapphire/LED and many other applications - the demand for 3D surface measuring tools is enormous and is growing with new technologies and applications. Components and measuring tasks are becoming more and more complex, so that certain measuring tasks can often not be solved by one sensor alone, since the desired parameters are not directly accessible.

Interested in the more articles?

Part 2/5: Software Package „Lens Shape“

Part 3/5: New „Layer Mode“ for Field of View sensors

Part 4/5: Software package for overlay measurement

Part 5/5: Now even more features in the basic package

Several different sensor configurations can help to measure all relevant sample properties which are required to solve the task. Depending on the application, these can be measurements with different topography and (film) thickness sensors as well as different evaluations of the individual results. To achieve the desired output value, the individual results must be combined to achieve the desired final result. This approach is called "hybrid metrology". This is obviously a feature of our multi-sensor tools.

Due to our multi-sensor concept, the 3D surface measuring tools of the established MicroProf® series can be equipped with point and area sensors for topography measurement as well as with film thickness sensors. This makes it possible to solve a measurement task with different sensors, in which each sensor performs a measurement and the different results are combined.

The decisive step is that the measuring tool and the used recipe know the complete measuring task and fully implement it. This means that not only the measurements with all necessary sensors are carried out automatically, but the software also records the different measurement results and calculates the desired parameters from these.

Our Acquire Automation XT software enables the results of various measurements and evaluations to be combined in a following hybrid analysis, where the previously measured individual values are used to calculate new result parameters. The hybrid analysis tool has a very flexible design. In addition to basic calculation functions such as subtraction or multiplication, complex arithmetic operations are also possible. The hybrid analysis is simply configured in a separate dialog in which all input values and the output value(s) are defined with the specific calculation formula(s). After being configured, the hybrid analysis can be used in a fully automatic measuring process.

The layer stack is located on a wafer (opaque silicon substrate), a transparent oxide layer on top of it and an additional opaque copper layer in a limited area. If an optical topography sensor is used to measure the step height of the copper layer it actually measures the common step height of the opaque copper layer and the transparent oxide layer. In order to determine the thickness of the copper layer, a topography sensor is used to measure the thickness of the copper layer, including the transparent oxide layer. Furthermore, the thickness of the transparent oxide layer is measured separately with a film thickness sensor. By subtracting the oxide thickness from the total thickness determined previously, the desired step height of the copper layer is obtained.

We certainly have a solution for your specific task. Do not hesitate to contact us if you have any questions. Our experts will be glad to take care of your needs and work out individual solutions for you.

Interested in the more articles?

Part 2/5: Software Package „Lens Shape“

Part 3/5: New „Layer Mode“ for Field of View sensors

Part 4/5: Software package for overlay measurement

Part 5/5: Now even more features in the basic package