Via Filling is a technique that guarantees completely closed via holes.
Via Filling with Resin
The vias to be filled are filled with a special hole plugging resin, TAIYO THP-100 DX1 thermally curable permanent hole filling material, using a dedicated machine, ITC THP 30. The extra production steps needed, are performed before the 2-layer PCB production process. In case of making multi layers, this is after pressing.
- Drilling of only the vias that need filling
- Cleaning: plasma and brushing
- Black Hole
- Apply dry resist
- Imaging of ONLY the via holes
- Via hole galvanization (PTH)
- Strip dry resist
- Brushing if needed
- Baking: 150°C for 1 hour
- Via plugging with resin
- Baking: 150°C for 1.5 hours
After these steps the normal PCB production process starts or continues: drilling of the other PTH holes, and the normal outer layer production processes.
Using the IPC-4761 via protection type classification, this Via Filling type with Resin process ALWAYS results in a “Type VII – Filled and Capped” via.
Note: This Via Filling with Resin type is suitable for Via-in-Pad application.
|Via Filling with Resin|
|ToolSize / EndSize (mm)||Min||0.20 / 0.10|
|Max||0.60 / 0.50|
|Material Thickness (mm)||Min||1.00|
|Outer StartCopper Thickness (µm)||Min||12|
|IPC-4761 via protection type||VII – Filled and Capped|
- ONLY PTH holes (PTH hole = hole with copper pad on TOP and BOT side).
- ONLY through hole vias, so Blind vias can NOT have Via Filling.
Important parameters are resin content, aspect ratio of the hole and the thickness of the core involved. A complete filling can’t be guaranteed.
Avoid naming confusion between Via Filling and Via Plugging
The IPC-4761 via protection type classification, clearly defines the difference between
In our manufacturing processes we only use Via Filling as it has considerable advantages over Via Plugging.
Below is a short video explaining the process.
PCB Design Guidelines – Via Filling