Black White Sample Pack
Sample pack Black on White media
7 different materials
2" x 2" area
Black on White Sample Pack
This sample pack is a great opportunity to try and test various products we have for creating black on white reticles and targets - allowing you to work out which product conforms to your needs without committing to a larger order.
In the pack, there are 6 different formats - all of them presented in a 2" x 2" sample:-
- Black chrome with white plasticoat backing
- Black chrome with white plasticoat fronting
- Black emulsion film with white plasticoat backing
- Black emulsion film with white plasticoat fronting
- Black and white bromide paper
- Black chrome on translucent / 30% diffuser white glass
The design is a simple checkerboard pattern, with 5mm squares.
Soda Lime Glass is the most common substrate used for masks, due to its good quality/price ratio. The glass is optically good, very flat and has no imperfections. If used in a photo-lithographic process, glass can be used with a very wide variety of light sources from 350nm upwards, with an excellent UV transparency. Soda Lime glass has a thermal co-efficient expansion of 93 (10-7) which is approximately 10 ppm (parts per million) , and a transmittance value of 88% at 375-450nm, with a glass flatness class of 5um for the smaller plates and 10um for the larger plates. Some of the very big plates of 14" and above, may have a bigger flatness tolerance of upto 40um. We would recommend always using Soda Lime glass where it is suitable due to its relative inexpense.
Diffuser Glass White Diffusing Glass is a semi-opaque diffuser designed to create even illumination profiles. Unlike alternative materials, which create their diffusive properties through a coating or lamination process, the White Diffusing Glass is a solid diffuse material, allowing it to be used in any orientation. Because the surfaces are polished, the reflected light will be somewhat specular, while the transmitted light will be near-Lambertian. White Diffusing Glass is ideal for creating even illumination as an attenuator or as a viewing screen. Anti Glare coating can be added as an optional extra.
Bromide Paper Agfa silver haline , resin coated 0.2mm thick photgraphic bromide paper which has a photographic emulsion coated onto one side. These are low resolution semi matte papers specially manufactured for non-critical processes. They are both imaged, and inspected, in controlled environments which is crucial to their dimensional stability. For the most accurate films possible, please use this films in an environment of 21 deg C and 50% humidity.
Polyester Film These have the following component layers: a plastic base, a photosensitive emulsion layer (silver halide) and a backing layer. This plastic base is flexible polyester film, and has a thickness of 0.18 mm. The emulsion layer is composed of gelatine and silver halide. The final result is a ‘black’ image coated on one side of the polyester base. The density of the film is very high, typically Dlog of 4.5 – 5, giving it an excellent opacity to all common light sources.
Q: What is the smallest feature that you can do ?
A: This depends upon the resolution that we image at, the material that we use, the tone of the photoomask, and most importantly the feature type (Spot, square, line etc). This all makes it very hard to give a figure, but as a very rough guide we can make 2-3um on an "everyday" basis , and down to 1um and possibly below using our highest resolution services (please ask).
Q: How accurate are the features, what tolerances do you work to ?
A: This is dependant upon the resolution that we image the photomask at. The QUICK REFERENCE brochure in the DOWNLOADS section will give you a chart, specifying both feature and dimensional tolerances.
Q: What resolution should i pick ?
A: The higher the resolution, then the sharper the edges of the features, the smaller the features possible, the more accurate the features will be, the sharper the corners in of the features, and also the smoother the circles. Some customers will notice this difference straight away, some will hardly notice any difference. Every customer has different requirements and different priorities. If in doubt, chose a higher resolution to ensure your requirements are met, but we are happy to advise if you send us your database.
Q: What does the term POLARITY and FIELD mean ?
A: Polarity is the tone of the photomask. In layman terms, this is usually described as POSITIVE or NEGATIVE. When you draw your photomask design, polarity determines whether the features on the mask are CLEAR or DARK on the final plate. The field refers to the background tone of the mask. So, a DARKFIELD mask would have the items you have drawn as CLEAR, with the background of the mask as DARK. Obviously this is the opposite for CLEARFIELD, where the field behind is clear and the design features are DARK. Remember, this is polarity or tone of the mask that we manufacture, and NOT the polarity of the wafer you are using. If used in contact lithography, the tone of the photoresist that you use will also affect which polarity to order.
Q: I've designed my photomask with the wrong polarity - what do i do ?
A: We can use the original design file and simply reverse the tone of the photomask. This is much easier than supplying new data.
Q: What is Right Reading, Wrong Reading and Mirrored.
A: Right Reading Chrome side Down is the most common way to describe a photomask that will be used for contact lithography. When you hold the mask in your hands with the chrome side facing down closest to the wafer, the image on the mask will be correct or how it should appear on the wafer. This is equivalent to Wrong Reading Chrome side Up. For us to make this happen we have to Mirror the image of your photomask before we write it.