High Frequency Board with Mechanical Blind Holes

A 3-stage HDI high-frequency board with mechanically drilled blind holes, mixed material stackup of Rogers RO4350B, S1000-2M FR-4, and Rogers RO3003G2. Mechanical blind holes are drilled with a controlled-depth mechanical drill — cheaper than laser microvias and viable when the blind-hole diameter sits between 0.10mm and 0.20mm and aspect ratio stays modest. The board targets >1GHz signaling: RO4350B for digital high-speed and lower microwave, RO3003G2 for ultra-low-loss mmWave (Dk ≈ 3.0, very low Df), S1000-2M for mid-layer mechanical and thermal stability. Used in communication systems, automotive ADAS sensors and 77GHz radar, satellite communication, broadcast radios, and defense radio modules where the depth of each blind hole layer must hit a specified pad without the cost of full laser HDI.