Title :
Performance of metal ball grid array (metal BGA) package
Author :
Tanaka, Hirofbmi ; Tanaka, Junsuke ; Morita, Moritsugu ; Waki, Hiroshi
Author_Institution :
Mitsui Chem. Inc., Yokohama, Japan
Abstract :
For the transmission of high frequency signals, it is important to adopt the microstrip line structure in BGA packages. Metal BGA packages consist of a Cu/polyimide/Cu substrate system without an epoxy adhesive layer, such that its electrical characteristics are superior to other plastic package which include an epoxy resin insulator. It is easy to fabricate the 90 μm pitch fine pattern circuit due to the polyimide surface flatness. The polyimide layer in the chip mounting area is removed by chemical etching and a cavity down structure is formed by the mechanical stamping process. The reliability of the metal BGA was investigated. Good results were obtained for pressure cooker testing over 288 hrs. The dielectric constant (εr) of polyimide is 3.2 and tan-δ is 0.002 at a frequency of 11.3 GHz. These values are very good for the construction of microstrip line structures in BGAs. The pulse response of a 10 mm long 50 Ω line in the metal BGA was measured, and a rise time of 0.35 nsec was observed. This result indicates the possibility of a maximum operating frequency of more than 500 MHz
Keywords :
UHF integrated circuits; ball grid arrays; copper; dielectric losses; etching; fine-pitch technology; integrated circuit packaging; integrated circuit reliability; integrated circuit testing; microstrip lines; polymer films; surface topography; 0.35 ns; 10 mm; 11.3 GHz; 288 hr; 50 ohm; 500 MHz; 90 micron; BGA microstrip line structures; BGA packages; Cu; Cu/polyimide/Cu substrate system; cavity down structure; chemical etching; chip mounting area; dielectric constant; electrical characteristics; epoxy adhesive layer; epoxy resin insulator; fine pattern circuit; high frequency signal transmission; maximum operating frequency; mechanical stamping process; metal BGA; metal BGA package; metal ball grid array; microstrip line structure; plastic package; polyimide; polyimide layer; polyimide surface flatness; pressure cooker testing; pulse response; reliability; rise time; Dielectrics and electrical insulation; Electric variables; Electronics packaging; Epoxy resins; Frequency; Metal-insulator structures; Microstrip; Plastic packaging; Polyimides; Pulse measurements;
Conference_Titel :
IEMT/IMC Symposium, 2nd 1998
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5090-1
DOI :
10.1109/IEMTIM.1998.704502
