This paper gives results from HF measurements and simulation ofsequential build-up boards (SBU). An HF test pattern was designed toinvestigate SBU HF properties. SBUs were supplied by four manufacturers.The test SBUs contained patterns for crosstalk, impedance matching,stray capacitance and wire bonding. The boards had a double-sided FR-4core with two built-up layers on each side, but the HF test board wasonly on one side. Test patterns were located in layers five and six. Twoline spacings between signal and victim tracks of 50 μm and 100 μmwere considered. S-parameters were measured on a network analyser in the45 MHz-10 GHz range. In time domain test, near-end and far-end responseswere measured. Simulations used P-SPICE, HP MDS and a 2D finitedifference program. Impedance measurements and simulations wereperformed in layers five and six with conductor widths for 50 Ωand 55 Ω characteristic impedances. Line widths ranged from 40-65μm in layer five and 150-200 μm in layer six. Reference trackswere designed to estimate conductor and dielectric loss. In thewire-bonding test, two interconnect types were assessed: a solder jointand an isotropically conductive adhesive joint (ICA). A Si test chip wasused for wire-bonding on the SBU-board. Crosstalk measurements andsimulations agreed closely over 45 MHz-10 GHz. Small differences betweenthe three dielectrics were obtained, and dielectric loss is a limitingfactor in the HF range. For a test pattern length of 30 mm, the HF limit(-3 dB transmission loss), was 2-3 GHz in layer six and 3-4 GHz in layerfive. Measured characteristic impedances ranged from 44-63 Ω
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