TAIWAN - Compact designs coupled with increasing functionality in the handset industry is driving a trend towards more layers in high-density interconnect (HDI) boards. Two upcoming high-end handsets will reportedly use a four-layer stack-in structure, according to industry sources.

Layer density has increased from single- and double-layer boards, and an increasing percentage of high-end handset products require three-layer HDI boards.  Companies such as Unitech Printed Circuit Board have seen  three-layer HDI boards reach 20% of sales, according to GM Cheng-Hung Hsu. While these boards are already common in the industry, two high-end handset vendors have started manufacturing four-layer HDI boards, with shipments scheduled for September.

The four-layer boards reportedly sell for a 50% higher price over three-layer, a significant profit for those who produce them, but Hsu points out that the current produced three-layer boards are already capable of meeting design requirements for high-end handsets. Given the typical design trends towards smaller size and greater functionality however, it is likely that more manufacturers will follow the lead.

With the move toward higher layer board configurations, Hsu also speculated about a possible shortage of HDI boards used for handsets, given the economic slowdown keeping manufacturers conservative on expansion.

Read more ...