By Dr. Phil Garrou, Contributing Editor
It’s been awhile since we looked at what is new on the dielectric market so we checked with a number of dielectric suppliers and asked what was new in their product lines.
Dow Chemical
The old Rohm & Haas organization has been running the Dow Electronics Materials business for a while now, basically since they were acquired by Dow. I knew they would do well when I observed them make the ill advised low-K SILK product quietly go away.
They certainly have beefed things up in the BCB product line as follows.
- Toughened BCB has been developed with 3X the elongation at some expense to CTE
- A Dry film grade is being developed with thicknesses up to 100um
- A positive-tone, aqueous developable product, BCB, 6505 is fully commercialized
- A BCB based temp bond adhesive, XP-130215, for wafer thinning and 3D stacking is being sampled
I have compared the properties of a few of these new products to standard photo BCB 4000 below.
| Property | Cyclotene 3000/4000 | Cyclotene 6505 (aq dev) | Toughened BCB | BCB Dry Film |
| Cure temp (˚C) | 210-250 | 210-250 | 210-250 | 200-250 |
| Tg | 350 | 350 | 350 | 250 |
| Dk | 2.7 | 3.2 | 2.7 | 2.6 |
| CTE (ppm) | 42 | 45 | 70 | 63 |
| Tensile Strength (Mpa) | 87 | 99 | 93 | 80 |
| Elongation (%) | 8 | 13 | 25 | 13 |
| Residual stress | 28 | 29 | 24 | 28 |
| H2O uptake (%) | 0.25 | 1.1 | 0.3 | 0.1 |
The PI community has not been standing still either. PIs always known for their high temp stability and their superior mechanical properties has had some catching up to do when it came to curing temperature amongst other properties.
HD Micro offers the following product lines.
C-4 flip chip RDL layers:
– HD 4100 negative tone photo PI
– HD8800 positive tone photo PBO
– HD 8900 positive tone low cure temp photo PBO
2.5/3D Adhesives:
– HD 3000 non photo temp adhesive
– HD 7000 photo PI permanent adhesive
Stress Relief and Passivation Layers:
– PI 2545 non photo wet etch PI
– HD 8800 positive tone photo PBO
– HD 8900 positive tone photo PBO low cure temp
Properties of these materials are compared below:
Zeon
Zeon is introducing the new positive tone photo “olefin based” Zeocoat CP 3010 designed to deliver a low cure temp, low stress coating. Below are the properties of the polymer determined after a 180 C cure.
| Property | Zeocoat CP3010 (cured at 180 C for 1 hr) |
| Water Abs (ppm)
(130 C;98%RH;100 hr) |
1750 |
| Mod (GPA) | 2.9 |
| CTE (ppm) | 51 |
| Stress (MPa) | 23 |
| Tensile Strength (MPa) | 97 |
| Tg ( C) | 196 |
| Dielectric constant (1MHz) | 2.9 |
| Leak current (A/cm2) @2 MV/cm | 1.0 e -10 |
| Breakdown Voltage (MV/cm) | 6.5 |
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