KMSF® 1000 Low Stress Photo-dielectric
Part of the StructSure™ Line
KMSF® 1000 is a negative tone, polyimide-based photo-dielectric for use as an ultra-low stress buffer, passivation or protective layer. This innovative material provides exceptional warpage control, making it ideal for thin and large diameter substrates used in backend assembly processing. Its low shrinkage, very low tensile modulus, and minimal thermal cure requirements ensure reliable performance. Film thicknesses of ~ 3 to 10 µm can be achieved in a single coat
Wafer size/thickness: 200 mm/50 µm
Material film thickness: 10 µm
20 µm via
10 µm Film Thickness
50 µm via
10 µm Film Thickness
15 µm L/S
10 µm Film Thickness
Cured Film Properties
| Mechanical Properties | |
|---|---|
| Young's Modulus | 0.14 GPa |
| Tensile Strength | 37 MPa |
| CTE α1 (<Tg) | 140 ppm/°C |
| Elongation | 160% |
| Residual Stress | 0.2 MPa |
| Electrical Properties | |
| Volume Resistivity | 1.8 x 1015 Ohm cm |
| Electric Strength | 1.8 kV/10 µm |
| Dielectric Constant, 1GHz | 2.6 |
| Dissipation Factor, 1GHz | 0.008 |
| Thermal Properties | |
| Tg (TMA) | 57°C |
| 5% Weight Loss Temperature in N₂ | 420°C |
| Water Absorption | |
| Moisture Absorption (23°C/85%RH, 24 hours) | 0.1% |
Key Features
- i-Line/broadband sensitivity
- 1:1 aspect ratio imaging
- Solvent development
- Low temperature cure < 200°C
- Excellent thermal & chemical stability
- No warpage due to low shrinkage and tensile modulus.
- High electrical reliability enabled by
- very low moisture absorption
- No Post Exposure Bake required
Process Parameters
Coat
KMSF® 1000 resist is offered in a standard viscosity of 260 cSt. The relationship between film thickness and spin speed is illustrated in Figure 2, based on tests conducted with a Brewer Science® Cee® 200 coater. The tests used a static dispense method on 6″ (150 mm) silicon wafers, followed by a soft bake at 110°C on a leveled hot plate.
*Please note the exact thickness obtained may be slightly offset from Figure 2. due to equipment type, setting differences and room conditions,
Recommended Program
1.Dispense 1 ml of resist for each inch (25 mm) of substrate diameter
2.Spin at 500 rpm for 5–10 seconds with acceleration of 500 rpm/second
3.Spin at 1000-4000 rpm for 30 seconds with acceleration of 500 rpm/second
Soft Bake
A 110°C soft bake for 3 to 10 minutes on a level hotplate with good thermal control and uniformity is recommended. KMSF® 1000 film remains slightly tacky after soft bake thus hard contact exposure should be avoided.
Exposure
KMSF® 1000 is compatible with i-Line and broadband exposure tools. The film typically remains tacky after soft bake therefore, hard contact alignment should be avoided. Bulk film thickness loss associated with exposure and development is typically observed. The film loss is a function of the exposure dose as depicted in Figure 4. Higher doses result in lower film loss and higher final film thickness. For minimum film loss, a broadband exposure dose greater than 400 mJ/cm2 (high pressure Hg vapor lamp) measured at 365 nm is recommended.
Development
KMSF® 1000 resist is optimized for development in solvent-based KMSF® Developer using immersion, spray, puddle or spray/puddle methods. A typical spray puddle process at 23˚C would be 70 rpm, 60 seconds spray, 60 seconds puddle followed by a 60 seconds spray