Solder bump structure for flip chip semiconductor devices and method of manufacturing therefore
View Patent ↗The invention provides, in one aspect, a semiconductor device that comprises an interconnect layer located over a semiconductor substrate. A passivation layer is located over the interconnect layer and having a solder bump support opening formed therein. Support pillars that comprise a conductive material are located within the solder bump support opening.
1. A method of fabricating a semiconductor device, comprising:
providing a semiconductor substrate having an interconnect located thereover;
creating a solder bump support opening in a first passivation layer located over the interconnect;
depositing a lithographic resist layer in the solder bump support opening and over the passivation layer;
patterning the lithographic resist layer to form spaced apart sacrificial posts within the solder bump support opening;
depositing a conductive material between the spaced apart sacrificial posts and within the solder bump support opening;
removing the lithographic resist layer, thereby leaving the conductive material within the solder bump support opening to form support pillars within the solder bump support opening, wherein removing the lithographic resist layer includes leaving a space between at least one of the support pillars and the sidewall of the solder bump support opening; and
depositing a second passivation layer over the first passivation layer and between the support pillars;
removing a portion of the second passivation layer from between the support pillars, such that the second passivation layer remains within the space between at least one of the support pillars and the sidewall of the solder bump support opening;
forming an under bump metallization (UBM) layer over and between the solder bump support pillars.
2. The method recited in claim 1 , wherein the UBM layer is located over the second passivation layer.
3. The method recited in claim 1 further including forming a barrier layer on exposed surfaces of the spaced apart sacrificial posts.
4. The method recited in claim 1 , wherein the conductive material comprises copper.
5. A method of fabricating a semiconductor device, comprising:
forming an interconnect layer over a semiconductor substrate;
forming a passivation layer over the interconnect layer;
patterning the passivation layer to form a solder bump support opening therein;
forming support pillars within the solder bump support opening, the support pillars comprising a conductive material; and
forming an under bump metallization (UBM) layer located over the support pillars, wherein the UBM layer is located between at least one of the support pillars and a sidewall of the opening formed in the passivation layer and contacting the sidewall of the opening.
6. The method recited in claim 5 wherein a portion of the UBM layer is located within the opening and between sidewalls of the passivation layer that define the opening and at least one of the support pillars.
7. The method recited in claim 5 , wherein the support pillars include a barrier layer that is located on the interconnect layer and on the support pillars.