Below is a list of some of the most frequently asked questions with answers.

Q1. Can the X35-186H-1 (two component) adhesion be improved with adhesion promoter
A1: The X-35-186H-1 has excellent adhesion characteristics to glass, metals and ceramics, and there is no need to add any adhesion promoter to this.

Q2. Can PMC be changed from 150C to 175C to decrease time?
A2:Yes, most probably 1hr would be OK at 175 degree C. We can provide data to support this.

Q3. Is there a significant effect for thickness differences between say 50um and a few milimeters?
A3:Most basic material performances don’t depend on the thickness.

Q4. What is the acceptable mixing ratio error allowed? (ie. 10:0.9 – 10:1.1)
A4: The acceptable error is +/- 2%, so 10 : 0.98 ~ 1.02 is the acceptable range

Q5: What is the pot-life of X35-186H-1?
A5: Shin-Etsu define potlife as being the time at 23°C at which viscosity increases more than 20%. 16 hrs is the specification.

Q6: Can the materials be supplied in pellets form?
A1: No. The compression molding materials are supplied in liquid form.

Q7: What is the required curing time on the molding machine & what is the full curing cycle
A7: The general starting recommendation is 90s @ 180C on the machine followed by 4 hours @ 150C post mold curing.

Q8: Are LPS 5547 & 5538 suitable for Metal Lead Frame molding – transfer or compression molding?
A3: Yes, the LPS-5547 and LPS-5538 are suitable for Metal Leadframes and compression molding. Neither material is suitable or can be used in transfer molding.

Q9: In case it comes only in liquid form – please advise for suitable mass production systems that are build for injection of pre-mixed molding material
A9: We have extensive experience and relationships with both TOWA and ASM for compression molding these silicones for LED devices, but we can support these activities with other suppliers also.

Q10: What about adhesion of LPS-5547 & LPS-5538 to Chips, Ceramics, Glass and other polymers
A10: Both the LPS-5547 and LPS-5538 have excellent adhesion characteristics to glass, metals and ceramics, and there is no need to add any adhesion promoter to this. As far as other polymers are concerned, these need to be tested on a case-by-case basis.

Q11: Are there materials that are suitable for transfer molding?
A11: Yes, Shin-Etsu have developed a line of highly reflective SWC transfer mold silicones for use as the reflector of the LED. These materials are transfer molded, but due to their highly complex and peculiar processing conditions, Shin-Etsu have taken this process in house and have agreed to supply the SWC ONLY as a premolded packages. These packages (known as “Tiger Leadframes” can be either metal leadframe, PCB or ceramic.

This list will be updated as questions are asked and data becomes available.

For more information regarding Shin-Etsu X35-186H-1 or any other Shin-Etsu silicone for LED assembly, please visit us or contact us for more details.

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CAPLINQ is proud to support Shin-Etsu in this highly specilized product line which uses traditional semiconductor industry transfer mold equipment to premold SWC grade silicone onto preplated leadframes (PPF). These premolded, preplated “Tiger” leadframes aim to completely replace the industry’s current PPA premolded package or substrate with a superior, cost-effective solution that can withstand high temperature and long-term UV exposure for LED and solar cell manufacturers.

Starting in 2010, Shin-Etsu plan to fully commercialize and sell these turn-key premolded leadframes that can withstand the much tougher requirements of high power LED applications and solar cell packages. Typically, ceramic packages have been considered as the only viable alternative to the industry standard PPA premolded plastic housings to withstand higher temperature and UV conditions.

For more information regarding Shin-Etsu premolded “Tiger” LF” leadframes, please visit us or contact us for more details.

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LINQTAPE PIT1S has a backing thickness of 1mil (25 micron) and the adhesive layer adds another 1.5 mil (36micron) for an overall thickness of 2.5mil (60 micron). The new PIT0.5S has a backing thickness of 0.5mil (13 micron) + 1mil (25 micron) adhesive layer for an overall thickness of 1.5 mil (38 micron).

This product is only available to registered users (customers can be added manually after registration) but the price is the same as LINQTAPE PIT1S.

To prepare a tape with an overall thickness of 25 micron could be possible, but the minimum order quantity would be one master roll of 20″ (510mm) width or the equivalent of about 20 rolls of 1 inch (25.4mm) tape.

For more information about polyimide tapes or any other of our products, visit us or contact us for more details.

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• Sputtering metals on silicon wafers
• Study the inter-metallic layers formed during metal deposition
• Study the metal-polyimide interface
• Carry out X-ray photoelectron spectroscopy

The first test is to determine the thermal robustness of the CAPLINQ LINQTAPE PIT1SD and PIT2SD (double-sided, polyimide tape with silicone adhesive; 1mil and 2mil thick backing respectively). For the purpose of wafer metal deposition, Dr. Markus Lützelschwab, an R&D Engineer in the Optics & Packaging department of CSEM (Centre Suisse d’Electronic et de Microtechnique SA) carried out this test in Switzerland. He did some preliminary tests by sticking the PIT1SD and PIT2SD onto a glass container and heating the assembly using a hot-air solder tool. Using this test, he demonstrated that it showed the same thermal robustness as [single-sided] Kapton tape.

After this step, Dr. Lützelschwab sent the wafer with the LINQTAPE polyimide tape for a sputtering process. The LINQTAPE withstood easily the externally conducted sputtering process of Titanium and Gold. Attached is the picture of one corner of the LINQTAPE polyimde tape after sputtering.

For more information about polyimide tapes or any other of our products, visit us or contact us for more details.

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Silicone and Acrylic adhesive applied polyimide films are used for various coil wrappings including Tesla Coils, gold-finger masking, high-temperature masking, splicing, temporary bonding of thermocouples for oven profiling, insulating circuit boards, and other applications that require both the properties of the polyimide film as well as the adhesive properties provided by either silicone or acrylic.

CAPLINQ also offers non-adhesive polyimide film (PITN-Series). This product has been successfully tested as a release film in a welding press that fuses PTFE-coated (Teflon-coated) composite conveyor belting (made of glass-fabric). This process previously used a silicone impregnated glass, but some customers do not like the silicone release cloth burn-off and therefore this alternative method, using adhesive-free polyimide film was developed.

For more information of copper wire bonding, visit us or contact us for more details.

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KJR-4013E is a flexible, moisture-cure silicone most often used as junction-coating resins in the manufacture of diodes. KJR-651E, KJR-655E and KJR-657E are rigid thermoset polyimide-silicones used as junction coating resins in the manufacture of higher power diodes and thyristors. Both are used due to their excellent adhesion to epoxy molding compounds (EMC), high humidity resistance, and excellent volume resistivity and dielectric breakdown properties.

To be able to conduct failure analysis, customers have asked if there is a process to remove the cured silicone / polyimide-silicone from the diodes and/or thyristors (decap).

One recommendation is to use sulphuric acid (H2SO4) which can normally clearly strip organic compounds.  Nitric acid (HNO3) is another option.  If the dissolving rate is slow, adding heat to the process helps very much.  Of course, for either of these processes, a fume hood is necessary all the time.

For more information of copper wire bonding, visit us or contact us for more details.

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Silicone-based adhesives are certainly more standard, but sometimes the customer needs acrylic because they cannot have silicone in their systems, need higher adhesion at mid-range temperatures or other specific reasons.

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The Usual Suspects

Generally speaking, manufacturers use three different adhesive types in combination with the backing material to produce a final “tape” product. Though these adhesive types can be subdivided into subgroups, the main categories are as follows:

1. Silicone
2. Acrylic
3. Rubber

Each of these adhesive types have advantages and disadvantages which make them more or less suitable for particular applications. Here we will draw the major lines outlining these differences.

Silicone adhesives

Silicones have been used to formulate adhesive products for decades due to their flexibility, temperature cycling resistance, chemical resistance, and wide range of possible material properties.

Silicone adhesives have the following general characteristics:

• High flexibility (low modulus) at sub-ambient temperature
• Consistent performance over wide temperature range (a reason they work so well with Polyimide Tapes)
• Excellent ageing and UV resistance (a reason they work so well in LED applications)
• High temperature resistance
• Good resistance to polar solvents

Compared to acrylic and rubber adhesives, they are significantly more expensive, but due to their excellent high temperature performance they are very well suited to splicing tapes, masking tapes and polyimide (Kapton) tapes.

Acrylic Adhesives

Acrylic adhesives can either be water-based (this is also referred to as emulsion or dispersion) or solvent-based. Water-based are slower drying compared to solvent-based systems but generally solvent-based acrylic systems have better resistance to other solvents, chemicals and water. Comparatively, water-based systems are less expensive than their solvent-based counter parts.

Acrylic adhesives are generally divided into two subgroups: Pure and Modified

Pure acrylic
Pure acrylic adhesives share the following characteristics:

• Reasonable adhesion to a wide range of substrates (see modified acrylics below)
• Good ageing, transmittance and UV resistance (a reason they are often used in fiberoptic applications
• Reasonable temperature resistance; between silicones (high resistance) and rubber (low resistance)

Pure acrylics have a lower tack (“stickyness when dry” for the layman) and less adhesion on hard-to-bond plastics such as high- and low-density polyethylene (HDPE & LDPE) and polypropylene (PP) than modified acrylic or rubber adhesives. Pure acrylic adhesives are mainly used on tapes whose applications are bonding, sealing or surface protection.

Modified acrylic
For all intents and purposes, modified acrylics have the same characteristics as pure acrylics, but have superior adhesion to the hard-to-bond-plastics mentioned above. Generally, these are more expensive than pure acrylics and are used for plastic bonding (including vinyl and linoleum), lamination and splicing.

Rubber Adhesives

Just from looking at the roll, it is very hard to tell what type of rubber is used on the tape. Look at the figure to the right, and this same picture can be used to describe every type of rubber-tape below. The key is to ask the supplier what type of rubber adhesive is used. Like acrylics, rubber adhesives can be divided into two subgroups: Natural and Synthetic

Natural rubber
These adhesive have higher tack (again “stickyness when dry” for the layman) than acrylic adhesives as well as higher shear strength but they have limited UV resistance. These are used in the cheapest tapes on the market, but have limited applications. Natural rubber adhesives are used in duct tapes, low-temperature masking tapes and surface protection tapes (think of the tape you get on your new fridge or stove).

Synthetic rubber
As the name implies, synthetic rubber is “formulated rubber” – think coming from the lab, not coming from the tree. Synthetic rubber can broken into three subgroups: Hot-melt, Solvent and Butyl rubber.

Hot-melt rubber

Hot-melt is a low-temperature melting plastic, which makes this adhesive have low temperature resistance. It also ages poorly (becoming brittle) and has low UV resistance. This rubber is used for low- to medium-duty carton sealing, low-temperature splicing as well as paper core starting applications.

Solvent rubber

Solvent-rubber based adhesives have better temperature and aging performance but still poor UV resistance. It is used for electrical and foam tapes.

Butyl rubber

Butyl rubber based tapes have excellent UV and aging resistance but lower mechanical strength. These tapes are used in foam tape applications and construction and plumbing applications such as pipe joints.

Visit CAPLINQ.com today or ask us how we can help you select the right tape for your application.
tapes are mainly used for sealing applications in the building and construction industry. T

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Shin-Etsu offer a range of silicone materials suitable for optical fiber coating.

Depending on the equipment and method of polymerization (UV Cure of Heat Cure), different categories of products are available. Refer to the figure below.

Primary Coating Material

For the primary coating, there is one heat-cure product (OF-182), and two UV-cure products (OF-211 and OF-212). These products exhibit specific optical properties as the light (data) travels through this layer. For these applications a refractive index of 1.49 – 1.52 is required and all these products have refractive indices that fall in this range.

Buffer Coating Material

The buffer coating material is used to keep the light (data) within the fiber core and thus requires a material with a much lower refractive index, typically in the 1.41 – 1.44 range. For this application, there are two heat cure products (OF-101 and OF-180) and two UV-cure products (OF-207 and OF-208).

These materials are suitable for normal telecon fibers coated with 400µm – 500µm thicknesses at line speeds of 100 to 500 m/min.

For more information on these or other products, please visit us or contact us for more details.

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Polyimide Tape is made up of two separate steps. First is the manufacture of the polyimide film itself and the second is the application of the adhesive backing.

The Polyimide Film Manufacturing Process

Polyimide film, the generic name of of DuPont’s tradename Kapton®, is synthesized by polymerizing PMDA and ODA in strong polar solvents through the process of forming film and imine treatment at high temperature. This synthesis creates excellent physical, chemical, and electrical properties, as well as atomic radiation resistance, solvent resistance and low & high temperature resistance. It performs well in a wide range of temperatures as low as -452°F (-269°C) and as high as +500°F(+260°). Because of these characteristics, it is uniquely suitable for specific for many high temperature applications.

Manufacturing Polyimide Silicone PSA Tapes

Polyimide Silicone Adhesive Tape is made by first taking polyimide film and coating it with a heat-resistant silicone adhesive. Due to its stable pressure-sensitive macromolecule adhesive layer at high temperature, the tape offers excellent properties of heat resistance, electrical insulation, solvent resistance and radiation protection. Being silicone, it offers better elongation at break, and is used for electrical insulation of electrical equipment and high temperature insulation. It offers the highest heat resistance among film adhesive tapes, so it can also be applied for insulation in high-end electronic equipment, motors, and Lithium (Li) batteries. Other applications include the protection of the gold fingers on Printed Circuit Boards (PCBs) during wave soldering, as lead-free solders often require reflow temperatures up to 260°C – an operating temperature for which polyimide tape is uniquely suited – leaving no adhesive film once the tape is removed. Finally (though the true list of applications is nearly endless), it can be used for shielding in high temperature applications.

Manufacturing Polyimide Acrylic PSA Tapes

Polyimide Acrylic Tape is made using the same process as the silicone process described above, but though the acrylic is typically a heat-resistant acrylic, it still cannot withstand the high temperature range of the silicone PSA described above. Also, acrylics tend to be more brittle, so the lower temperature range is also somewhat more limited as the adhesive can crack at extremely low temperatures. However, since the polyimide acrylic tape still uses a base of polyimide, the film itself is still able to withstand a wide temperature range and can still be used in many of the same high-temperature applications; it is just that the adhesion properties of the film become more limited with an acrylic adhesive. Acrylic chemistries are typically cheaper materials also, so the final selling price of acrylic-based polyimide tapes are generally lower.  Though CAPLINQ offers both acrylic-based and silicone-based tapes; given the marginal price difference and the wider range of applications, the most popular tapes remain the silicone-based polyimide tapes.

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