Method for etching deep groove of back lighting type image sensor

Abstract

The invention relates to a method for etching a deep groove of a back lighting type image sensor. The method comprises the following steps that after a device wafer is in bonding with a logic wafer, etching is carried out on oxide on the surfaces of the wafers until a tetraethoxyethyl silicon layer is exposed; an isolation oxide layer is deposited on the etched surfaces; a bottom anti-reflection layer and a low-temperature oxide layer are formed on the isolation oxide layer in sequence, and the low-temperature oxide layer is coated with a photoresist layer; photoresist patterns are manufactured, and an opening is formed in the photoresist layer; etching is carried out on low-temperature oxide exposed below the opening of the photoresist layer, and an opening is formed in the low-temperature oxide layer; etching is carried out on the bottom anti-reflection layer below the opening of the low-temperature oxide layer, and an opening is formed in the bottom anti-reflection layer; deep groove etching is carried out on the opening area on the bottom anti-reflection layer until the metal on the top portion of the logic wafer is exposed. A groove manufactured through the method is high in depth-to-width ratio and etching quality is high.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit manufacturing process method, in particular to a deep trench manufacturing method. Background technique [0002] When the size of the device is reduced, the area on the surface of the wafer used for isolation between circuit devices will also be relatively reduced. These surface area isolations can be etched using deep trenches on silicon wafers (silicon wafers), and then filled with appropriate dielectrics or conductors. Substance to reduce the area it occupies in the morning. For super junction devices, pressure sensitive sensor devices, high power devices, image sensors and other manufacturing processes, deep trench technology is widely used. Deep trenches are formed in the substrate of the silicon wafer, and all subsequent devices and wiring structures are built on the deep trenches, so deep trench etching has a special status in the entire process flow. [0003] In the traditional etchi...

AI Technical Summary

Problems solved by technology

[0003] In the traditional etching method, the etching ability of the etchant used for high aspect ratio is not improved. When etching the trench with high aspect ratio, the phenomenon of etching stop will occur before the etching reaches the predetermined depth.

In addition, due to the poor selectivity of the etchant to the photoresist, the problem of insufficient photoresist residue, that is, during etching, the photoresist will be consumed so that the predetermined line width cannot be achieved, resulting in The critical dimension of the trench cannot be controlled

Using traditional methods to fabricate high aspect ratio trenches has poor productivity, low product yield, long process time, and increased costs

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