Fine pitch TAB technology with straight side wall bump structure for LCD panel

A wafer-bumped TAB (tape automated bonding) device called the fine-pitch TAB device, which has been applied to a LCD (liquid crystal display) panel designed for a flat-panel display, is introduced and described. The devices, fabricated with flat-surface bumps and a straight side-wall structure instead of the conventional mushroom structure, have several important features, i.e. (1) the shear strength has an average value of 8.65×10³ gr/mm², (2) the inner lead pitch (the bump pitch) is 100 μm in the mass products, and a pitch of about 40 μm is achieved in the test vehicle. The technique utilizes a triple layer of intermediate metals consisting of titanium, nickel, and palladium, applies the bump photoengraving process using a dry-film resist, uses the cyanide electroplating technique, and uses the ILB (inner lead bonding)/OLB (outer lead bonding) equipment with higher alignment accuracy