Wafer Bonding Seal Ring

Wafer to wafer bonding and packaging dr.

Wafer bonding seal ring.

One such technique is wafer level packaging wlp which forms a hermetically sealed cavity in which the device element is situated. Deposited on patterned si bonding ring. The pair of seal rings for example is arranged in parallel. Finally polymer cap encapsulation combining the merits of wafer to wafer bonding and thin film packaging has been reported.

1 surrounds the main device area 110 and is parallel to the outer perimeter of the die. Due to the concave regions un etched bond rings when the cap wafer comes into a contact with a planar device wafer only the concave seal area un etched area gets bonded. These results demonstrate that bonding with the cusn thin film sealing ring at 400 c. Article osti 1107804 title wafer level packaging with compression controlled seal ring bonding author farino anthony j abstractnote a device may be provided in a sealed package by aligning a seal ring provided on a first surface of a first semiconductor wafer in opposing relationship with a seal ring that is provided on a second surface of a second semiconductor wafer and.

Most of the metal seal bonding technologies require metal frames on both wafers as shown in figure 32 1. As a solution bcb dry etching has been proposed to. The bottom wafer generally was a 300µ m thick 4 si wafer having a low bow and a low total thickness variation ttv. Eutectic ausi bonding is the only method where only one joining partner requires a metal frame.

The seal ring 150 as shown in fig. 17 21 it consists of a polymer membrane as a packaging cover and a polymer sealing ring. With advances in wafer bonding technology this process has been widely applied to the fabrication of mems devices. Bcb sealing ring has shown partial bonding or full bonding depending on its flatness.

Metal layer bonding pattern seal rings and bond pads photolithographically eutectic bonding uses eutectic point in metal si phase diagrams to form silicides au and si have eutectic point at 363 c. This paper presents the effect of bcb sealing ring flatness on bcb bonding for wafer scale bcb cap transfer packaging. Thara srinivasan lecture 25. The bond seal area is defined by etching the backside of a cap wafer by 2 µm.

Sealing rings after eutectic wafer bonding. It is found that the principal cause of the partial bonding is due to non flat bcb sealing ring caused by multilayer bcb coating process. Finally both cap and interposer wafers were bonded together using a wafer to wafer bonder and an adapted ausn soldering process scheme. Here a cap wafer is manufactured with a gold ring metallization and the mems wafer provides a silicon frame area for the metallurgical reaction.

A material a b c d e f cap dicing.