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1、IPC4761 via typeType Cat I I-a Description Tented Via figure process Remark I I-b Tented Via II II-a Tented and Covered Vias Tented Via (Type I Via): Single Sided Tented Not A via with a dry film mask material Recommended applied bridging over the via wherein no additional materials are in the hole.
2、 It may be applied to one side (Type I-a) or both sides (Type I-b) of the via structure. Process: Vacuum laminated film material that is photo-definable. A Type I via with a secondary covering of mask material applied over the tented via. The material may be applied to one side (Type II-a) or both s
3、ides (Type II-b) of the via structure. Process: Application of mask over Type I. A via with material applied allowing partial penetration into the via. The plug material may be applied from either one side (Type III-a) or both sides (Type III-b) of the via structure. Process: Screened and Roller Coa
4、ted. A Type III via with a secondary covering of material applied over the via. The plug and secondary covering material may be applied from either one side (Type IV-a) or both sides (Type IV-b) of the via structure. Process: Application of mask over Type III. A via with material applied into the vi
5、a targeting a full penetration and encapsulation of the hole. Process: Screened, roller-coated, or squeegeed. Single Sided Tented and Covered Not Recommended II II-b Tented and Covered Vias III III-a Plugged Via Single Sided Plugged Not Recommended. III III-b Plugged Via IV IV-a Plugged and Covered
6、Via Single Sided Plugged and Covered Not Recommended IV IV-b Plugged and Covered Via V V Filled Via VI VI-a Filled and Covered Via Dry Film Cover VI-b Filled and Covered Via Dry Film Cover VI-a Filled and Covered Via Liquid Film Cover VI-b Filled and Covered Via Liquid Film Cover VII Filled and Capp
7、ed Via VI VI A Type V via with a secondary covering of material (liquid or dry film solder mask) applied over the via. The covering material may be applied from either one side (Type VI-a) or both sides (Type VI-b) of the via structure: Process: Application of mask over Type V. Fill material can be
8、electrically and/or thermally conductive depending on end use. VI VII A Type V via with a secondary metallized coating covering the via. The metallization is on both sides: Process: Metallized coating over Type V. Applicable where high density features are required. Partially Filled Via Though not i
9、dentified as a via protection type, this document does recognize manufacturing processes where solder mask flows into the hole during liquid solder mask application, without intending to provide complete coverage or protection, and may result in partial plugging. This is not acceptable with bare cop
10、per surface finishes. The illustrations below show typical via configurations when liquid solder mask is used with no specific process for via protection. Inconsistency of coverage can lead to a mix of all configurations on the same board. Process should not be implemented over bare copper. If the final finish is HASL the center of the hole wall will be bare copper.
