Title :
Process and design analysis for ultra fine-pitched wiresweep elimination in advanced copper heat spreader BGA package
Author :
Chungpaiboonpatana, Surasit ; Shi, Frank G.
Author_Institution :
Henry Samueli Sch. of Eng., California Univ., Irvine, CA, USA
Abstract :
The semiconductor device trend for increasing functionalities and performances yet with smaller overall feature sizes presents escalating obstacles to the decreasing form factor along with demanding thermal carrying capability required at the package level. To confront this compounding issue, ultra fine pitch wirebond interconnect coupled with thermally enhanced copper heat spreader attached to the package are introduced. But the additional copper heat spreader thickness introduced within the package challenges the design of the package´s wire, its loop height, and the molding process control to prevent wire sweeping occurrences. This study investigates the impact of different ultra fine pitched wire types, wire loop designs, copper heat spreader structures, and mold material types on eliminating device short from occurring due to the wire sweeping phenomena. A full factorial experiment is performed using an active silicon device packaged in a thermally enhanced BGA test vehicle. In addition, test characterization is carried out using X-ray and multi-insertions hot/cold continuity tests. Then, a detailed failure analysis is performed by chemical decapsulation to confirm the experimental findings. In conclusion, the study finds that for an ultra fine pitched thermally enhanced BGA package, wire type is insignificant to reduce wire shorting occurrences. However, mold material and copper heat spreader structure using an optimized wire loop design are significant factors in eliminating wiresweep shorting phenomena. This study concludes,with a Wirebond interconnect and heat slug design recommended along with an improved process parameters and assembly material sets found from the experiment.
Keywords :
ball grid arrays; copper; design of experiments; encapsulation; failure analysis; fine-pitch technology; heat sinks; thermal management (packaging); transfer moulding; advanced copper heat spreader BGA package; assembly process; design analysis; device short; failure analysis; full factorial experiment; heat slug design; mold material types; process analysis; thermally enhanced copper heat spreader; ultrafine pitch wirebond interconnect; ultrafine-pitched wiresweep elimination; wire loop designs; Copper; Performance evaluation; Process control; Process design; Semiconductor device packaging; Semiconductor devices; Silicon devices; Testing; Thermal factors; Wire;
Conference_Titel :
Electronic Components and Technology Conference, 2004. Proceedings. 54th
Print_ISBN :
0-7803-8365-6
DOI :
10.1109/ECTC.2004.1320305