Wafer-level chip size encapsulation technology for GaAs (gallium arsenide) CCD (Charge Coupled Device) image sensor

Abstract

The invention relates to a wafer-level chip size encapsulation technology for a GaAs (gallium arsenide) CCD (Charge Coupled Device) image sensor. The technology is characterized by comprising the following steps of: (1) firstly bonding a glass wafer and a GaAs wafer through a resin adhesive so as to protect the active surface of a chip and improve the strength of a chip wafer; (2) manufacturing a trapezoidal-slot structure by a wet corrosion or physical method so as to reduce the lining thickness of a chip interconnection area; (3) manufacturing vertical interconnected through holes by a dry etching technology so as to expose a pad on the active surface of the chip; (4) sputtering seed-layer metal and electroplating, and manufacturing a hole metalizing and RDL layer to realize circuit interconnection from the active surface to the back surface of the chip; (5) manufacturing a passivation layer, a UBM layer and raised points; and (6) finally scribing to form an independent encapsulation chip. As the trapezoidal-slot structure on the back realizes thickness reduction only in the area with the pad, the cost is effectively lowered; and through the interconnection of the vertical through holes, the encapsulation interconnection density can be improved, and the signal transmission path is shortened.

Description

technical field [0001] The present invention relates to a GaAs CCD image sensor wafer-level chip size packaging process and structure, more precisely relates to a GaAs CCD image sensor wafer-level chip size packaging process realized by adopting trapezoidal groove structure and vertical through-hole interconnection technology, GaAs The CCD image sensor is a MEMS (MicroElectroMechanical System, Micro Electro Mechanical System) sensing device, and therefore belongs to the field of MEMS device packaging. Background technique [0002] MEMS refers to a system made of micro-fabrication technology, integrating micro-sensors, micro-components, micro-actuators, signal processing, and control circuits. MEMS devices have very broad application prospects in many fields, and image sensors, as a kind of MEMS devices, are particularly widely used. The pixel structure of image sensors is extremely susceptible to contamination and damage, which affects its performance. Wafer-level chip size...

AI Technical Summary

Problems solved by technology

Its feature is that the extended pad is used to make trapezoidal grooves on the side of the image sensor, thereby forming a T-shaped connection. The trapezoidal grooves can be machined or plasma-etched. The disadvantages are high process costs, low reliability and interconnection density. Low

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