CAPLINQ has been working with a number of LED customers lately, and many of the same questions keep coming up regarding the Shin-Etsu X35-186H-1, a screen-printable silicone suitable for phosphorus suspension in LED applications as well as other silicones for LED assembly.

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.

Native Tapioca starch, even food-grade tapioca starch is a world commodity and CAPLINQ knows that it must compete against a global market of producers. Despite this, we believe that our tapioca starch prices, produced in Gabon, Africa are very competitive and when you include sea freight charges to South Africa, Europe, and South America – our prices are even more competitive.

Consistent with CAPLINQ’s general pricing practices, we believe that these prices shouls also be transparent and open for all (including our competitors) to see. For this reason, CAPLINQ is pleased to announce and publish a public price list of its Native Food-Grade Tapioca Starch.

Volume-Based Native Tapioca Starch Prices | Cassava Starch

Prices are effective March 2010 – FOB Libreville, Gabon and subject to change without notice
Prices are based on a 20ft (6m) container with a capacity of 1,172 ft³ (33.18 m³):

• 100MT – USD$380/MT
• 1000MT – USD$370/MT
• 5000MT – USD$360/MT

Click for more information regarding Native Tapioca (Cassava) Starch, or please contact us for more details.

Recently, Shin-Etsu launched a new line of products codenamed “Tiger LF”. These “Tiger” leadframes are Shin-Etsu’s answer to the LED and solar market to replace the industry’s conventional PPA plastic housing with a premolded leadframe using Shin-Etsu’s patented Silicone Molding Compound – its SWC-Series products.

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.

After several years of representing Profound Material Technology Co. Ltd. (PMTC) Tin/Lead and Leadfree (Pb-free) solder spheres to its existing customer base, CAPLINQ has announced plans to sell solder spheres online. Working closely with PMTC, CAPLINQ will start with a narrow product offering of its most popular products, namely PMTC Eutectic Sn63Pb37 for its customers who still use Tin/Lead spheres, PMTC Leadfree SAC305, its most popular industry standard Pb-free solder spheres and PMTC Leadfreee SAC405, its second most popular industry standard for Pb-free processing.

Each of these solder ball product offerings will be available in the full range of sphere diameters, from 0.075mm (3 mil) in diameter for flipchip and wafer scale packaging up to 0.76mm (30 mil) for ball attachment of Ball Grid Array (BGA) and Chip Scale Packing (CSP) applications. In order to best serve its small and middle-size customers, as well as cater to CAPLINQ’s high volume users, CAPLINQ will offer low volume packaging to its smaller customer and also high volume pricing for its best customers. All prices and volume breaks are posted on CAPLINQ’s website.

For more information about Tin/Lead (SnPb) or Leadfree (Pb-free) solder spheres or any other of our products, visit us or contact us for more details.

Many customer have requested whether CAPLINQ can offer thinner polyimide tapes. CAPLINQ is pleased to announce LINQTAPE PIT0.5S a 0.5mil (13 micron) Polyimide Film with a 1mil (25 micron) silicone adhesive.

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.

When customers look at the technical datasheet (TDS) for LINQSTAT Volume Conductive Film, they often are confused by the Electrical Properties. The 3M Velostat material lists only Volume Resistivity as less than 500 ohm-cm, yet the LINQSTAT material lists Volume Resistivity, Volume Conductivity and Surface Resistivity. The fact of the matter is that they are all related, and if you know the Volume Resistivity of the material and the thickness of the sheeting, then you can calculate the other values.

Surface Resistance multiplied times the thickness of the material in centimeters, equals the volume resistivity.

Volume Resistivity vs. Volume Conductivity

Volume Resistivity is also called bulk resistivity because it is the inherent resistance of a semiconductive material independent of shape or thickness. Very simply, resistivity is the inverse of conductivity. Volume Resistivity is measured in Ohms-cm, or spoken as “ohms-centimeter” and Volume Conductivity is measured in S/cm, or spoken as “Siemen per centimeter”. Therefore, a Volume Resistivity of 500 ohm-cm is equal to a Volume Conductivity of 1/500 or 0.002 S/cm.

Volume Resistivity vs. Surface (or Sheet) Resistivity

Surface Resistivity (also called Sheet Resistivity) is expressed as Ohms/sq, spoken as “ohms-per-square”. It is a useful measurement when measuring a layer or thin film of a semiconductive material such as LINQSTAT as the surface resistance of a given material will change depending on the thickness of the layer. Surface Resistance (ohms-per-square) multiplied times the thickness of the material in centimeters, equals the volume resistivity (ohms-cm). Likewise, the Volume Resistivity divided by the thickness in centimeters equals the surface resistivity.

Therefore, looking at the LINQSTAT VCF materials, the surface resistivity of each material can be determined based on the thickness of the film and the volume resistivity (<500 ohm-cm)

• VCF-2xxxxS-Series: 500 ohm-cm / 2mil (0.00508cm) = 98,425 S/cm
• VCF-4xxxxS-Series: 500 ohm-cm / 4mil (0.01016cm) = 49,213 S/cm
• VCF-8xxxxS-Series: 500 ohm-cm / 8mil (0.02032cm) = 24,606 S/cm

Why does CAPLINQ give “less than” values (ie. <500 Ohm-cm) instead of Typical Values?

LINQSTAT Volume Conductive Film is a carbon-loaded polyethylene. As such, there are necessarily some differences in the conductivity over the entire surface. The data that CAPLINQ provides is meant to be a minimum, repeatable value that can be used in the design of the final product.

For more information on LINQSTAT VCF-Series, please contact us or visit the CAPLINQ website today to find out more, or for more information.

CAPLINQ LINQTAPE Polyimide Film can be used to sputter metals, including precious metals like Gold (Au) and Titanium (Ti). This may be done for various reasons including:

• 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.

We recently had a customer ask us several questions about our LINQTAPE PIT1S / PIT1A Polyimide tapes.  We have posted the questions as long as the answers below:

Q1. What’s the minimum polyimide film thickness?
A1. Our thinnest standard material is 1mil (0.025mm).  We can produce thinner, but there would be minimum order quantities associated.

Q2. Could we provide free samples of PIT1A?
A2. As you can imagine, CAPLINQ receives many, many requests for “free samples”.  The manual entries, paperwork and ultimately costs that resulted from working outside our current workflow system (ensuring correct ship-to addresses, price quotes, samples lists, follow-up, etc.) was not in line with the low-cost model that we try to bring to our customers.  As such, we have done away with minimum order quantities and implemented a way to order single units instead of shipping free samples.

Q3. What is the heat resistance? We require it above 200C for 1-2 hours.
A3. The temperature resistance depends on the application.  The polyimide film itself can withstand temperatures of 450 °F (~230 °C) and for short periods, can withstand temperatures as high as 900 °F (~480 °C).  The weak point is the adhesive system.  The silicone adhesive (PIT1S-Series) can maintain adhesion above 200C, as well as short (2-3 minutes) periods at 260C.  Above this temperature, adhesion drops off quickly.  Acrylic-adhesives (PIT1A-Series) have a lower temperature resistance, but at lower temperatures (Room temperature) have a higher adhesion than silicones.  Depending on the application (namely masking), it is quite reasonable that the PIT1S could withstand 200C for 2 hours.

Q4. Under a certain degree of temperature an pressure, would the glue be coming out from the edge?
A4.  It is imaginable that under pressure at high temperature that the adhesive layer is compressed.  Whether and how far it would come out from under the polyimide backing, we have no data for.

Q5. What is the lowest thickness that can be produced, and will the thickness influence its heat resistance ability?
A5. I need to check with production what the minimum thickness is, but no, heat resistance is independent of the film thickness.

As a manufacturer of polyimide tapes and films (generic version of Kapton), we are often asked whether we can make custom-made shapes and sizes to meet advanced packaging requirements. The requests come from design engineers looking to incorporate polyimide films into their designs, often to create an insulation layers between two parts.

CAPLINQ offers this service and can even supply this for fairly low volume applications. For example, the image shown is a 3mil (0.003″ or 0.075mm) polyimide film with a custom-shape with maximum outside dimensions of 19.4mm x 9.4mm.

Below is CAPLINQ’s pricing for such a request:
#1 A one-time tooling charge of USD$150

#2 Price per part is volume dependent. Lower prices are available for even higher-volumes:
a) 500 Pieces: USD $1.50 /each
b) 1000 Pieces: USD $1.10/each
c) 2000 Pieces: USD $1.00/each

For your no-obligation quote or more information about polyimide tapes or any other of our products, visit us or contact us for more details.