Wafer Bonding Seal Ring

Wafer to wafer bonding and packaging dr.

Wafer bonding seal ring.

The seal ring 150 as shown in fig. This paper presents the effect of bcb sealing ring flatness on bcb bonding for wafer scale bcb cap transfer packaging. The bond seal area is defined by etching the backside of a cap wafer by 2 µm. These results demonstrate that bonding with the cusn thin film sealing ring at 400 c.

Finally polymer cap encapsulation combining the merits of wafer to wafer bonding and thin film packaging has been reported. With advances in wafer bonding technology this process has been widely applied to the fabrication of mems devices. Here a cap wafer is manufactured with a gold ring metallization and the mems wafer provides a silicon frame area for the metallurgical reaction. The polymer caps can be implemented through sacrificial etching and a wafer level transfer technique.

Finally both cap and interposer wafers were bonded together using a wafer to wafer bonder and an adapted ausn soldering process scheme. The seal ring in one embodiment includes a pair of seal rings i e a first seal ring 150a and a second seal ring 150b. One such technique is wafer level packaging wlp which forms a hermetically sealed cavity in which the device element is situated. A material a b c d e f cap dicing.

Eutectic ausi bonding is the only method where only one joining partner requires a metal frame. 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. Sealing rings after eutectic wafer bonding. Most of the metal seal bonding technologies require metal frames on both wafers as shown in figure 32 1.

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. The bottom wafer generally was a 300µ m thick 4 si wafer having a low bow and a low total thickness variation ttv. 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. Thara srinivasan lecture 25.

The cap wafer was equipped with 200 μm deep dry etched cavities and electro plated au seal rings around them. Deposited on patterned si bonding ring. 1 surrounds the main device area 110 and is parallel to the outer perimeter of the die. 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.

As a solution bcb dry etching has been proposed to.