Denso multilayer PCB halves cost

Citation

(2002), "Denso multilayer PCB halves cost", Circuit World, Vol. 28 No. 4. https://doi.org/10.1108/cw.2002.21728dad.007

Denso multilayer PCB halves cost

Keywords: Denso, Multilayers, Printer circuit boards

The Denso multilayer PCB can halve costs by using the following process steps:

1. 1.

   Imagine a base material which consists of copper foil laminated with PEEK resin and cured (two-layer)

2. 2.

   A plastic film is laminated on the resin side and conductor pattern is etched on the copper side.

3. 3.

   CO² laser is used to drill blind via holes on the film (resin) side.

4. 4.

   Paste is screened into the holes and semi- cured, then the film is peeled off, allowing slight protrusion of resin for subsequent adhesion to mating copper conductor pattern.

5. 5.

   Multiple number of such "double-layer" cores are prepared in parallel and then laminated together in "one shot".

6. 6.

   Final pattern is etched on two outer copper layers.

The concept is very similar to "ALIVH" developed by Matsushita Electric Industry. The major difference is in the lamination step. In the case of ALIVH (Any Layer Interstetial Via Hole), when vias are filled there is no copper (base material is Aramid prepreg). After via fill, coppor is laminated on both sides of the via-filled "prepreg", cured and then pattern is etched. Then, additional layers are added from both sides of the "base". This base becomes another "base" for subsequent lamination. In other words, the process is "sequential build-up" while PALUP process can be done in one lamination step to form multi-layer structure.

Apparently, the idea came from ALIVH process and the author of the article is referring to cumbersome "conventional multi-layer process", with ALIVH process in mind, not really the "conventional multi-layer process" you and I know, which is made in one "shot lamination process" after necessary inner layer cores are made in parallel. The author does not seem to be familiar with PWB technologies and blind- foldedly wrote the article based on information supplied from Denso which really "copied" ALIVH process.

The only difference between conventional Multi-layer board production process is that there is no plating necessary as in the case of ALIVH (Ni/Au plating is needed if this is the preferred surface finish).

Denso formed "PALUP Consortium" which comprises the Wako Corporation, Airex, Kyosha(SSG plant in Tijuana, Mexico), Noda Screen (hole filling specialist) and O.K. Print (using Orbotech LDI).