JUNCTION STRUCTURE AND METHOD OF MANUFACTURING THE SAME
A junction structure and a method of manufacturing the same are provided which can achieve stable wire bonding between a Poly-Si film bonding pad and an Al wire. The junction structure is made up of a SiO 2 film 5 formed on Si 4 , a BPSG film 6 formed on the SiO 2 film 5 , a SiN film 7 formed on the BPSG film 6 , a Poly-Si film bonding pad 1 formed on the SiN film 7, and an Al wire 2 bonded on the Poly-Si film bonding pad 1 . A pad surface average roughness 8 of the Poly-Si film bonding pad 1 can be reduced. Thus it is possible to reduce gaps between bonding surfaces of the Al wire 2 and the Poly-Si film bonding pad 1 and increase a bonding area, thereby improving wire bonding characteristics.
1 . A junction structure comprising:
a SiO 2 film formed on Si;
one of a BPSG film and a PSG film formed on the SiO 2 film;
a SiN film formed on one of the BPSG film and the PSG film;
a Poly-Si film formed on the SiN film; and
an Al wire bonded on the Poly-Si film.
2 . The junction structure according to claim 1 , wherein the Poly-Si film has a surface average roughness not larger than a surface roughness of one of the BPSG film and the PSG film.
3 . The junction structure according to claim 1 , wherein the Poly-Si film has a surface roughness not larger than 22 nm.
4 . The junction structure according to claim 1 , wherein the Poly-Si film has a thickness not smaller than 200 nm.
5 . A method of manufacturing a junction structure, comprising the steps of:
forming a SiO 2 film on Si;
forming one of a BPSG film and a PSG film on the SiO 2 film;
forming a SiN film on one of the BPSG film and the PSG film;
forming a Poly-Si film on the SiN film; and
bonding an Al wire on the Poly-Si film.