For a variety of specific requirements BMT devised and built measurement devices. Many different industries gained by our experience to build highly innovative gauges, e.g. engineering, electronics, paper and glas industry, semiconductors, medical technology, research institutes.
We will be pleased to solve your measurement tasks if you turn to us.
Optical Wafer Warpage Measurement System
The measurement station consists of a unique linear air bearing stage with an integral air bearing rotary table.
This has originally been developed specifically for wafer warpage measurement for a German wafer manufacturer. It can be used for wafers upto 300 mm diameter. These stages are an integral part of a single granite block. The unit consists of a massive granite block and features a moving stage made from aluminum with a hard anodised surface, 400x400x50 mm, with integrated air channels, vacuum preload, and can accommodate a vacuum chuck. The side rails are granite with a linearity of 1 µm.
The whole unit sits on passive anti vibration dampers and on a metal frame. The linear stage is driven by a steel band with DC motor/gear to minimise vibrations. Inside the linear stage rests a rotational air bearing table, diameter 300 mm, running coplanar on the granite base surface with vacuum preload and DC motor with gear and encoder.
The profile (warpage) measurement is made such that one takes a profile line across the wafer and then rotates the wafer by a certain angle and again makes a profile, etc. So all profile lines add up to a star-like graph which is evaluated. (in the picture you see a tactile pick up but naturally we will provide an optical sensor according to the customer’s requirements, e.g. an optical displacement sensor working according to the confocal principle. It has small enough a spot size to resolve details of the surface and lends itself well for surface profiling.
The controller of the sensor is a PC card. The sensor is attached to the granite bridge of the granite base unit via a manually adjustable Z displacement stage.
Windows 8 data controlling and data acquisition software. After setting the required parameters (data point density, travel length, etc.) the measurement can be started on a mouse click and the results will be displayed and can be saved or sent to another PC.
Further details on request.
Turbine Blade Measurement System
This measurement system has been built In order to measure precisely the leading edge profile. It employs tactile pick ups because an optical measurement proved unfeasible due to adverse circumstances (strong contrast variation, high slopes, vibrations and others).
Within an overall measurement time of a few seconds the blade profiles are measured in several sections and the profile lines are related to fixed reference points.
This gauge is efficient, simple to service, easy to operate and has an excellent price/performance ratio.
Using an optical technique instead of the pick-ups for this application proves to be extremely difficult due to strong contrast variations of the blade, high slopes and vibration issues among other challenges.
More details on request.
Glass lens thickness measurement
This measurement station is used to simultaneously measure the surface profiles on both sides of a workpiece. From this data the thickness at certain locations or the thickness profile (lines and areas) can be calculated. All relevant parameters such as data point density and measurement speed can be set. In order to minimise the inevitable drift the sensors are calibrated with a thickness standard when in the resting position.
The workpiece it is driven towards the operator for loading and removing The software runs under Windows 8.
The measurement station features a granite base plate with a bridge to which the sensor holder is attached. Two opposing sensors are mounted to this holder. Each sensor can be adjusted such that the two measurement spots coincide.
The measurement uncertainty for the line and flatness profile is < 0.1 µm.
Specific Roughness Measuring Instruments
BMT develops many customised gauges which are designed for specific workpieces or must meet specific requirements. Examples:
- Profile/roughness measurement of sheet metal to be painted using special parameters to describe the adhesive ability of the surface
- Roughness measurement inside bores with diameters < 1mm
- Roughness measurement and evaluation for the visual assessment of surface structures, e.g. plastics covers in cars
- Determination of the oil retention volume on honed surfaces, evaluation of homogenity, percentage of pore area, torn-and-folded-metal formation.
- Roughness measurement on gear teeth
- Roughness measurement on polished surfaces like wafers.
Laser textured sheet metal