A deep silicon via etching method

Abstract

The invention provides a through-silicon-via (TSV) etching method. A silicon wafer to be processed is arranged in a plasma processing chamber, the surface of the silicon wafer includes a graphical mask layer, the steps of etching and deposition are carried out circularly and alternatively until a through via with a target depth is formed, etching gas is led into a reaction chamber in the step of etching to etch a silicon substrate, openings are formed, and fluorocarbon gas is led in the step of deposition to protect the lateral walls of the openings formed in the step of etching. The TSV etching method is characterized in that the step of gas exhaust is included between the step of etching and the step of deposition, and leading-in of the etching gas or deposition gas is stopped in the step of gas exhaust. By means of the TSV etching method, arc lateral walls of the etched through via are prevented from being generated.

Description

technical field [0001] The invention relates to the field of plasma processing, in particular to a deep hole silicon etching method to obtain better sidewall morphology. Background technique [0002] In the field of semiconductor manufacturing technology, in the fields of MEMS (Micro-Electro-Mechanical Systems, micro-electro-mechanical systems) and 3D packaging technology, it is usually necessary to etch deep via holes in materials such as silicon. For example, in crystalline silicon etching technology, deep through-silicon vias (Through-Silicon-Via, TSV) have a depth of hundreds of microns, and their aspect ratio is even much greater than 30, and are usually etched by deep reactive ion etching. Bulk silicon is formed. Said silicon material is mainly monocrystalline silicon. After the etching is completed, conductive materials such as copper are filled into the holes or grooves formed by etching. The filling method can be chemical vapor deposition (CVD) or physical vapor d...

AI Technical Summary

Problems solved by technology

Such an opening structure is not conducive to the deposition of conductive materials in the next step. The smaller opening sidewalls above will block the further deposition of conductive materials in the holes below. It is likely that after the hole is filled with conductive materials, there will still be cavities in the holes.

The existence of these cavities will not only deteriorate the conductive characteristics, but even cause disconnection of the lines that need to be conducted.

This unfavorable sidewall morphology cannot be eliminated by adjusting the adjustable parameters in the traditional Bosch etching method

This causes the holes formed by the traditional Bosch etching method to cause problems in subsequent processing, and eventually leads to the abandonment of the entire product, resulting in a lot of waste and loss

Images