Factor 2: Stencil Printing and Solder Paste Management

Solder paste deposition is arguably the single most critical step for micro-miniaturization yield.

• 1. Nano-Coated Stencils and Laser Cut Precision: Stencils used for 01005 must be exceptionally thin (often $<100 \mu m$) and manufactured with high-precision laser cutting. Furthermore, a nano-coating on the stencil dramatically improves paste release from the tiny apertures, ensuring consistent solder volume.

• 2. Fine-Grain Solder Paste: Standard solder paste often contains granules too large for 01005 apertures. Type 4 or Type 5 ultra-fine-grain solder paste must be used to ensure the paste prints cleanly and uniformly.

• 3. Automated Solder Paste Inspection (SPI): 3D SPI is mandatory. This technology measures the volume, height, and area of every single solder deposit before component placement. Detecting insufficient or excessive paste volume at this stage prevents the majority of future defects (opens, shorts, tombstoning).

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