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Question
#929
Subject: The sputtering method of metallization appears to be more versatile. Will this process overtake the regular web metallisation process?
The sputtering method of metallization appears to be more versatile as various materials can be coated on substrate and at lower vacuum.Will this process overtake the regular web metallisation process with ceramic boats and higher vacuum.
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#930
Author: ,
Email:
Subject: There are advantages and disadvantages to both processes...
While the sputtering process may permit the coating of a wide range of materials and in some cases form a denser layer it is a low speed process relative to the physical evaporation especially for aluminum which is most often used for packaging and decorative applications. In these end uses the first most important barrier it supplies is light barrier followed by moisture barrier and then oxygen or aroma depending on the product (see Converting Magazine March 2002 for more details). In some cases the vacuum level can be important in the moisture and oxygen barrier development but for most metallization substrates the vacuum level is sufficient and is only a problem if the vacuum pump maintience is overlooked.
Consequently, for packaging and other decorative applications it is unlikely that the sputtering process will supplant that of the evaporation (physical vapor deposition) process as the speed penalty is to great to remain competitive.
For optical applications the sputtering may be better and the product price will support the higher process costs
Eldridge M. Mount III
585-223-3996
www.emmount-technologies.com
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#951
Author: Charles A. Bishop, C.A.Bishop Consulting Ltd.
Email: cabuk1@freenetname.co.uk
Subject: Sputtering is a more complex high precision deposition process.
Sputtering is a more complex high precision deposition process. Typically it is used only where some specific property cannot be achieved by the more simple evaporation. The cost of sputtering machines is anywhere from 3 to 10 times the cost of a vacuum metallizer and the deposition rates are often 100 times slower and hence the cost of the
metallized product is much higher. Products that benefit from magnetron
sputtering are ones such as the transparent conducting coatings like indium tin oxide (ITO) where it is required that the ITO to become conducting has an oxygen deficiency of a few parts per million. This level of control is only available to a high uniformity very stable source. Other products deposited by this process are multilayer optical filters such as used in solar control for the automotive and architectural industries, thin electrical conductors for patterned circuits and some security coatings.
An advantage of sputtering over evaporation is the higher energy of deposition. The depositing material has some energetic species that bombards the coating and hence any poorly bound material is sputtered off the growing coating hence the adhesion of sputtered coatings is often superior to those that have been evaporated. This also reduces the tendancy to columnar growth for very thick coatings however this is at the cost of much slower deposition rates.
Between the two processes is electron beam deposition where an electron beam is used to melt and evaporate the material. This can be configured to provide a linear source up to 1m wide per electron beam gun thus giving similar uniformity to sputtering also there are some energetic species and so there can be some increase in adhesion over resistance heated evaporation. This can be enhanced by use of additional plasma sources sited between the source and the substrate. This, like sputtering, can be used for reactive processes to convert a metal evaporated from the source to an oxide, nitride or carbide by the introduction of the appropriate gas. The cost of electron beam technology is similar to sputtering but the deposition rates tend to be higher. The control is not as precise as sputtering and hence each manufacturer has their preferred source technology for the range of products they make.
Sources of products and website information.
Southwall Technologies Inc. www.southwall.com
Sheldahl Inc. www.sheldahl.com
Flex Products Inc. www.ocli.com
CPFilms Inc www.cpfilms.com
Bekaert Speciality Films LLC www.bsf.com
I hope this answers your questions.Regards
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