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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