Thick Film Design Rules
Validities
- The following rules are effective for the draft of thick film structures.
- These rules are continuously updated.
- The instructions are absolutely informative and represent only some guide lines for a circuit design.
Thick Film Design Rules
Materials
Substrate materials:
- Aluminium nitride ceramic (AlN)
- other ceramics in compliance with customer request
Substrates / Panel dimensions:
- standard: 4 x 4
- maximum: 4.5 x 4.5
Substrate thicknesses:
- standard: 0.635 mm (25 mil)
- minimum: 0.254 mm (10 mil)
- other thicknesses and shapes in compliance with customer request
Thick Film Design Rules
Ink systems
The thick film inks noted below can be used.
Conductor:
Multilayer / Insulation:
- Cross-over or multilayer structures with insulation / dielectric ink.
Thick Film Design Rules
Layers structure
Substrates printed on one side:
- Conductor lines recommended as the first printing level.
- Up to 3 conductor layers can be made with dielectric layer between them.
- Subsequent conductor layers will use the same conductor material as 1st layer.
- Multi layer structure is possible with filled via connections through the dielectric layers.
Substrates printed on both sides:
- Single back side layer (not connected to front).
- Drilled filled via connecting front to back side
Thick Film Design Rules
Layout rules
Distances of the printed structures to the substrate edge:
All of the following measures are valid for substrate edges as well as for scribe lines, in case of several single substrates were printed on one large substrate:
- distance edge conductor line: > 0.2 mm
- distance edge resistor: > 0.5 mm
- distance edge isolation: > 0.3 mm
- distance edge glaze: > 0.3
Thick Film Design Rules
Design of conductor lines:
Conductor lines in one printing level
Conductor lines are printed directly on the substrate or the dielectric respectively.
For the minimum conductor width the dimensions below must be kept:
| On substrate width (min) |
On dielectric width (min) |
AgPd>0.2 |
>0.2 |
|
Ag>0.2 |
>0.2 |
Au>0.15 |
>0.2 |
|
|
- When widths and distances are less than 0.25 mm, the distance between two conductor lines should be 0.05 mm larger than their width.
- When widths and distances of the conductor lines are greater than 0.25 mm, they can be printed in the same relation.
- Conductor lines can be printed at any angles to the substrate edge.
- When printing conductor lines on dielectric, a side distance to the dielectric edge of 0.3 mm must be guaranteed.
- When printing over the dielectric edge it is advisable to graduate the dielectric edge
Printing Capabilities
MSP-485 Precision Screen Printer:
- Mechanical repeatability of /- 0.0002" ~ 5 µm
- Advanced U-Lign IV system with two high resolution CCD cameras, enable to achieve a +/- 0.001 " ~ 25 µm layer to layer repeatability.
Actual Firing Capabilities
- Max Temperature - 1050 deg.C
- Typical Temp. Uniformity - +/- 2 deg. C
Dicing Capabilities
- Resolution - 0.2 µm.
- Accuracy - 2.0 µm.
- Repeatability - 1.0 µm .