SCD Requirements
(Specification Control Drawing)

  1. Part size dimensions with tolerance, scale, units and smallest feature size clearly noted.
  2. Metal layers must include the following details by order. Thickness and tolerance must be listed:
    Resistor Layer 50Ω/sq. TaN, TCR -100±50ppm/°C
    Conductor Layer
    Tungsten-Titanium (WTi):
    Nickel (Ni):
    Gold (Au):
     
    500Å ± 100
    2,000Å ± 500
    100µ" ± 25µ"
    Solder Layer 4±1µm Pre-deposited 73/27 AuSn
    Ground Plane
    Tungsten-Titanium (WTi)
    Gold (Au):
     
    500Å ± 100
    100µ" ± 25µ"
  3. Substrate thickness, tolerance and finish must be identified:
    Alumina, as-fired 99.6%
    Thickness 0.025"±0.002"
    Surface Finish <4µ" CLA
    Camber 0.001"/"
  4. Specialty inspection requirements should be listed (i.e. bake testing, TCR).
  5. Customer name, customer part number and revision level must be listed on SCD.
  6. Resistance and/or capacitance charts should be provided:
    Resistor Nominal (Ω) TOL Length Width
    R1, R4 18.8 +5/-20% .0150 .0400
    R2, R5 15 +5/-20% .0150 .0500
    R3, R6 12.5 +5/-20% .0150 .0600
    R7, R10 16.5 +5/-20% .0150 .0450
    R8, R11 25 +5/-20% .0150 .0300
    R9, R12 50 +5/-20% .0150 .0150
    R13, R16 50 +5/-20% .0450 .0450
    R14, R17 16.5 +5/-20% .0150 .0450
    R15, R18 11 +5/-20% .0100 .0450
    R19, R22 25 +5/-20% .0200 .0400
    R20, R21 12.5 +5/-20% .0100 .0400
  7. Additional layers thickness and tolerance must be called out (i.e. SiN, polyimide).
    Dielectric layer 20,000Å ± 5,000Å Si3N4
  8. Additional layer properties must also be called out (i.e. 80/20 Au/Sn versus 70/30 Au/Sn).
    Solder layer 4±1µm Pre-deposited over 73/27 AuSn
  9. All pullbacks should be identified and dimensioned.
  10. Plating requirements must be defined.
  11. Front to back registration tolerance should be listed when applicable.
  12. Camber requirements should be listed.
  13. Filled vias must specify material Eg: Gold, Copper Tungsten, etc.
  14. Plated through-hole and via locations, diameters, and tolerances should be dimensioned.
* indicates required