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:

• Ag/Pd
• Ag
• Au
• Ag/Pt

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 .