Eric,

Several things effect solder bridging for SOIC's mounted on the wave solder 
side. Unfortunately, most are design related and if you can't change the 
design, then you are restricted as to what you can do.

1. Orientation

   Orient the parts (board) so the wave crest is perpendicular to the
to the long axis of the SOIC body.

2 Land Pattern

   Add two dummy lands (pads) to trailing edge of the part; essentially use
a 16 pin pattern for a 14 lead part

   Use soldermask between leads with no clearance; the soldermask pad is the 
same size as the copper pad

   Make the land as small as possible, 0.010-0.015" at each end of the
lead and 0.002" on each side of the pad; if you can't do an artwork spin,
change the soldermask to make the exposed solder surface of the land smaller

3. Shadowing

   Make sure that the wave isn't shadowed by adjacent parts; keep parts at 
least 0.100" from the SOIC body

   Provide a clearance of at least 0.050" to adjacent pads of other components

4. Process

   Use a dual wave or hot air leveling wave process; if you can't do this, 
perhaps you could try a double pass, but I not sure that this will help
unless you readjust the wave between passes, the first pass being a "rough"
wave running deep and the second pass a "smooth" wave very shallow; this 
approximates a dual wave machine.

Harry Parkinson
603-884-6760

 
From:	US2RMC::"[log in to unmask]" "MAIL-11 Daemon" 25-JUL-1995 17:25:33.31
To:	[log in to unmask]
CC:	
Subj:	Solder Bridges on SMT SOIC's


     We have a big problem with Solder Bridging on our Bottom Side SMT 
     components in Wave Solder. These are Glued on at SMT then Waved in 
     Wave Solder. We have tried everything under the Sun and have 
     eliminated most of the Bridges but not all. Any suggestions.
     
     
     ERic Bernal at Pragmatech, Sunnyvale, Ca
     (408)734-0595
     [log in to unmask]


% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail1.digital.com by us2rmc.zko.dec.com (5.65/rmc-22feb94) id AA14040; Tue, 25 Jul 95 17:18:18 -040
% Received: from miso.wwa.com by mail1.digital.com; (5.65 EXP 4/12/95 for V3.2/1.0/WV) id AA18066; Tue, 25 Jul 1995 14:14:26 -070
% Resent-Date: Tue, 25 Jul 95 13:27:14 
% Received: from ipc by gagme.wwa.com with uucp (Smail3.1.28.1 #8) id m0sarHD-000FGhC; Tue, 25 Jul 95 16:12 CD
% Received: by ipchq.com (Smail3.1.28.1 #2) id m0saqls-0000GoC; Tue, 25 Jul 95 15:40 CD
% Old-Return-Path: <miso!pragma.pragma.com!ebernal>
% From: [log in to unmask]
% Date: Tue, 25 Jul 95 13:27:14 
% Encoding: 386 Text
% Message-Id: <[log in to unmask]>
% To: [log in to unmask]
% Subject: Solder Bridges on SMT SOIC's
% Resent-Message-Id: <"M5rFM3.0.DQ8.cQL5m"@ipc>
% Resent-From: [log in to unmask]
% X-Mailing-List: <[log in to unmask]> archive/latest/728
% X-Loop: [log in to unmask]
% Precedence: list
% Resent-Sender: [log in to unmask]