Film Laminated Custom Target
FILM LAMINATED TO GLASS TARGET
FOR PRICE, PLEASE REQUEST QUOTE
We have the ability to laminate our flexible patterned films to rigid materials. This can be used as a low cost alternative to large chrome or emulsion plates (although with reduced quality and accuracy), and can also be sued as a great alternative to "black on white" patterns due to the maximum size limitations of normal materials.
If the target that you require is transparent, then we laminate using an optically clear adhesive glue (OCA). If the target you need is reflective, then we add a white (or silver, or whatever colour) to the front - or back - of the film, and then laminate it to the glass support to give it rigidity.
We can supply almost any glass type and thickness for lamination as the base carrier. However, we are not limited to these materials, we can also laminate to other rigid bases such as metal or plastic sheeting.
All of our photomask films are imaged onto Agfa Idealine HPF (High Resolution Plotter Film) 0.18mm thick polyester film which has a photographic emulsion coated onto one side. These are specially manufactured for high resolution and consistent high quality results. 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.
Where a solid black pattern is required with high optical density, choose the option for "Monochromatic" films. However, if you need a greyscale image then you will require the "Greytone" film.
For the solid black monochromatic films, we can write masks at 4 different resolutions, called "grades". The higher the grade then the higher the resolution that we image it, giving a better quality and more accurate line widths. When imaging in Greytones, then we use a LPI (Lines per Inch) ruling to create a dithered / halftone pattern, and of course the higher the number of lines per inch then the better the quality.
The coating that we apply is a "plasticoat" paint that is spray coated over the surface of the film. In effect, there is a wide range of colours. The most common we use is White and Silver for reflectivity, but others are available. Please ask.
You also have to decide which surface to coat of the flexible film. The film is made up of a 0.17mm thick polyester base, and on top of that sits a gel emulsion with silver halide particles, and is it this gel that has the black pattern in it. The coating options are therefore:
Coating Over Pattern Side: Here, we take the film pattern side up and spray over the whole film, which then covers the pattern completely. So, the result here is 0.17mm polyester > pattern > base colour. Next, we turn the film upside down and laminate it to the glass, so that the pattern side is against the glass face . This is our suggested method because the pattern gel - which is delicate - is coated and protected against the glass side so that it cannot be damaged. It also means that the pattern and the base colour are on the same focal plane. However, this means that when viewing the target with your optical equipment, you will have to look through the 0.17mm polyester base to focus on the pattern. The polyester base can have imperfections such as bubbles that you will have to make sure are not in the focal plane.
Coating Over Polyester Side: This is the opposite, where we coat over the polyester side, so the result is pattern > 0.17mm polyester > base colour. The downside to this method is that the pattern and base colour are not on the same focal plane, and the top delicate pattern is exposed and can be damaged easily. However, a benefit to this method is that the pattern is very top of the target and therefore easy to focus without any possible contamination.
Anti Glare Coating : Provides a semi-permanent, non-gloss finish which protects and eliminates light reflection. Can be washed in water without any damage, and it can be removed with Acetone if no longer required. The nature of the coating means that it is an interference coating added to the surface, so this can distort line edges when viewed under high magnification.
CD means "Critical Dimension" and is often used to describe the smallest feature on the design. Feature in this instance can mean drawn data, and also spaces between drawn data. Putting a correct value here helps us determine inspection and production processes. Please use the NOTES section if you need to convey to us any other information.
Data formats listed above are only a small section of what is available. Please note that printing based formats such as Corel Draw, PDF, Postscript, SVG, BMP, TIFF etc are not created to allow sub micron positioning, and we often see these formats export data that can be inaccurate at the micron level. For all Class 3 and Class 4 type work, we strongly recommend using Engineering vector type formats such as Gerber, GDSii, DXF, CIF etc. If your chosen format is not listed, please contact us for further information and clarification. We are also able to provide a full drafting service whereby we can create your designs from drawings and descriptions.
Masks are normally referred to as Clearfield (positive) & Darkfield (negative)
Positive means that the data you have drawn in CAD will be Chrome on the mask, with the background (the field) being clear glass.
Negative is the opposite of this, where the items drawn on CAD will be clear and the background will be chrome.
We also need to know which way round the mask has been designed on your screen. The easiest way to select this is to add some reference text (anything you like) to the design somewhere - maybe in the corner - and then specify if the text needs to be right reading or wrong reading.
Our standard production turnaround is 3-4 days from receipt of the artwork, purchase order and related documents. We generally send checkplots with every order, and it is vital that these are replied to within a short delay in order that we can meet the schedule required. The production schedule assumes the original data package is correct and does not need to undergo revisions or changes. For large volume orders, or large photomasks on high resolutions, please enquire before ordering premium services.
Standard (3-4 days) : This is our standard service, and whilst we get 99% of orders shipped within this period, these are guidelines only and may change in periods of high demand. Where data packages are good, and all paperwork is completed promptly, we can often ship early. Expected return of checkplot by customer is within 4 hours. Any orders received after 1pm will assume day 1 to be the following day.
2 Days : A premium service. A complete manufacturing package (data/instructions/order) must be with us by no later than 11.00am. Expected return of checkplot by customer is within 1 hour.
Sameday: A premium service. A complete manufacturing package (data/instructions/order) must be with us by no later than 9.30am. Does not include Class 4 products, or photomasks bigger than 7". Expected return of checkplot by customer is within 30 mins.
5 Days + : This is a discounted service for orders that are not urgent. Note that typical schedule is 5-10 days .
Standard : We firstly inspect the piece by eye for flaws, design inaccuracies and contaminations. We also inspect a test coupon (placed in the bottom corner of the mask) for line width accuracy and edge definition. Next we measure the overall dimension of the mask, and record both of these measurements on our internal inspection records. Finally, we find the CD of the mask, measure that, record it, and also take a digital photo that is saved with the inspection log. We use Nikon MM40 at 900x magnification and an OGP ZIP 300 at 400 x magnifications for this.
Enhanced : In addition to the standard inspection process described above, we will then document them via a Certificate of Conformance which we supply with the mask. Tolerances are per our standard tolerances.
Full Certificate : By selecting this option during the ordering process, we will inspect upto 10 customer defined measurements, with customer supplied tolerances. You will need to send us a document, or a separate layer of the design, showing us where you want us to take the measurements from. There can be upto 10 positions defined by the customer. These dimensions are then programmed on the co-ordinate measuring system and the mask is compared to this unique program. A certificate of measurement /conformity is given if the mask passes the inspection process.
A method of sending an email copy of the design for verification before the mask is written. The ‘PDF Checkplot” is a low resolution (4000 dpi) graphic representation of the final photomask - the quality of the PDF does not represent the quality of the final photomask, it is a "gross overview". You must approve this by email before we can proceed. For more accurate checkplot representation , we can request a GerbTool CAD checkplot which will represent the design perfectly – in high resolution – and gives you the ability to also measure (you will need to install specific software for this method)
YOUR DRAWING NUMBER
Please let us know the CAD file name / number so that we can tie together the uploaded data and the order.
Here you can inform us of any other requirements or specifications regarding the order.
Please see the TECHNICAL sections, DOWNLOAD sections and FAQ for further information. If you still require clarification, pleas either email or click for LIVE SUPPORT.
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. It can be combined with Anti Glare coatings.
Quartz (Fused Silica) is not as common due to the expense of the material, but quartz brings the very best stabilised material thermally, along with a very clear base that allows a wide variety of wavelengths to pass through at very good transmission rates. The thermal co-efficient expansion is 5(10-7) which is approximately 0.5 ppm (parts per million). Flatness of this material is best-in-class, with 2um flatness for small plates, and 5um for mid sized plates. It can be combined with Anti Glare coatings.
B270 or BOROFLOAT® are made out of Borosilicate, and are ideal for high temperature and harsh environment applications. Unlike common borosilicate that is drawn flat, BOROFLOAT® is produced by a float technique that yields superior surface accuracy. BOROFLOAT® is about three times more resistant to thermal shock than standard soda lime glass, and has a thermal co-efficient expansion is 35 (10-7) which is approximately 4 ppm
The specification of the raw materials and the photo-resist, mean that there may be minor defects that appear randomly across the image. Usually these defects are cosmetic only, and most often the defect actually causes no working problem with the design. A defect is defined as having a size greater than the required rate, and can take many forms such as a "pinhole" in what should be the chrome/emulsion part of the mask, or it can be a chrome / emulsion spot in the clear part of the mask (also referred to as 'shorts' or 'breaks'). A defect is any flaw affecting the geometry that passes the authorised specification for the order.
The customer may indicate the size of defects that will affect their process (defect spec). All defects which break these rules must be repaired, or if they cannot be repaired, the mask must be rejected and rewritten. Where no defect spec is given by the customer, we use our own internal standards.
There is also a class of defects known as cosmetic defects. These are defects that may not affect the geometry but still may not be acceptable to the customer. Cosmetic defects include scratches on the chrome outside the array, damaged or partially removed AR coating, contamination on the chrome, glass chips on the edge of the mask, etc.
The Customer Defect Specification Form is to be used by customers to inform us of their defect specifications. It may be supplied to cover every order within a given time frame, or on a per order basis. If the form is not submitted, our own internal specifications take over. These specifications will be used by our front end engineers to asses if masks can be written before going into the write phase, and customers will be informed where specifications are deemed to be unachievable.
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 mask, 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 if we "hold it's hand through production" .
Q: How accurate are the features, what tolerances do you work to ?
A: This is dependant upon the resolution that we image the mask 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 mean ?
A: Polarity is the tone of the photomask, and in layman's terms it is what you might call Positive and Negative. When you draw your photomask design on your computer, you need to decide if the objects that you draw are going to be opaque on the photomask- and therefore to block the light - or transparent areas on the photomask. It's best to always think of the data that you draw either being positive data, or negative data. If used in contact lithography, remember, this is polarity or tone of the mask that we manufacture, and NOT the polarity of the wafer you are using.
Q: I've designed my mask with the wrong polarity - what do i do ?
A: We can use the original design file and simply reverse the tone of the mask. This is much easier than supplying new data.
Q: What is Right Reading, Wrong Reading and Mirrored.
A: Some people use the photomask in contact exposure, and others use it as an optical component. Making sure that the design is the corect way round is important. To inform us exactly what you need, it is best to add a title or reference text somewhere on the design and then we can talk in terms of "right reading" or "wrong reading ". Another way of thinking about "wrong reading" is to think of the text being mirrored. 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. Right Reading Chrome Up is maybe the most common way to describe optical components. However, every customer has different requirements from the next, so you need to inform us via the order form.
Q: So what would Negative Data - Right Reading Chrome Down actualy mean ?
A: Using the above Q&A's as a reference, we can now say that when you are holding the photomask plate in your hand, and the text is reading correctly, then the chrome will be on the underneath surface and the glass support is uppermost. The design will be an exact opposite - in tone - of what you had designed on the computer.