Title :
Optimization of the gull wing lead
Author :
Chen, Wayne ; Dody, Glenn ; Adamjee, Waseem
Author_Institution :
Motorola Inc., Austin, TX, USA
Abstract :
Summary form only given. The long-term reliability of fine-pitch gull wing leads was investigated in a temperature cycling environment of -40°C to 125°C. The test vehicle was a 208-lead fine pitch quad flat pack (FQFP) plastic package, with lead pitch of 0.5 mm. The leads were specially prepared in the following configuration: two different foot lengths, 0.5 mm and 0.8 mm; two different foot angles, 2° and 14°; two different lower bend radii, 14 mils and 21 mils; two different solder compositions, 63/37 Sn/Pb and 62/36/2 Sn/Pb/Ag; coplanarity for all leads of 1.4 mils or less; coplanarity of all eight corner leads deformed in the range of 1.5 to 2.9 mils; and coplanarity of all eight corner leads deformed in the range of 3.0 to 4.4 mils. A Taguchi experiment design with an L8 orthogonal array was employed in this investigation
Keywords :
design engineering; environmental testing; optimisation; packaging; reliability; soldering; surface mount technology; -40 to 125 degC; 0.5 mm; 0.8 mm; 208 lead QFP; 28 mil; 42 mil; FQFP; L8 orthogonal array; Sn-Pb solder; Sn-Pb-Ag solder; Taguchi experiment design; coplanarity; fine pitch quad flat pack; fine-pitch PQFP; fine-pitch gull wing leads; foot angles; foot lengths; gull wing lead; lead pitch; long-term reliability; lower bend radii; optimisation; plastic package; solder compositions; temperature cycling environment; test vehicle; Foot; Geometry; Lead compounds; Semiconductor device packaging; Semiconductor device reliability; Soldering; Temperature; Testing; Tin; Vehicles;
Conference_Titel :
Electronics Manufacturing Technology Symposium, 1991., Eleventh IEEE/CHMT International
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-0155-2
DOI :
10.1109/IEMT.1991.279754
