Dear Mr  S.
The sequential build up (SBU) process I assume you are asking about is the
HDI-Microvia one, not the mech drilled blind-buried via SBU process,
although both are the same process, the HDI  just with smaller vias.

Microvias have been around 20 years now.  HP and IBM used them in products
in the early 80's. Japanese took them up in the 90's for portable
products, now they are the fastest growing segment of the PCB market. ALL
cell phones are now SBU-microvia boards, as are ALL organic flip-chip
packages like the Intel Celeron or Pentium 4.  Most PDAs use microvia SBU,
as do more and more high-performance multilayers for networking and
telecom.  But some HDI-Microvia boards are not SBU (the IPC Type I is not)
because it is NOT sequentially laminated.

There are many Web Sites with information and design rules about SBU and
Microvias.  My Web Site has 25 articles you can download as well as price
and density comparisons between the two technologies.  You are welcome to
go to www.westwoodpcb.com

Good Hunting

Happy Holden
Westwood Associates





Murulidhara S <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
12/17/2003 01:32 AM
Please respond to "TechNet E-Mail Forum."; Please respond to Murulidhara S


        To:     [log in to unmask]
        cc:
        Subject:        [TN] sequential build up process


Dear Technetters,

I want to know about sequential build up process for MLB fabrication. Can
any one brief about the sequential build up process. Also let me know
related web sites regarding sequential build up process. Is this process
proven and recommended?

Regards,
Mr.Murulidhara S.
Deputy Chief Engineer ,
PCB and Chemical Lab - R&D,
ITI Ltd. ,
Dooravani Nagar ,
Bangalore
INDIA
PIN-560 016

Ph : 91-080-8503959
Fax : 91-080-5650971



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