Self-aligned nanometer through-silicon-via structure and method of preparing the same

A method of preparing a self-aligned nanometer through-silicon-via structure, comprising:

• step S1, providing a silicon substrate, wherein the silicon substrate comprises a fin structure perpendicular to a surface of the silicon substrate and extending upwardly, growing a first SiO2 layer on the silicon substrate, wherein the first SiO2 layer covers the fin and is located at a same height as the fin, so that a first structure is obtained;
• step S2, growing a sacrificial layer on a top surface of the first structure, forming a first preset pattern on a top surface of the sacrificial layer, sequentially etching the sacrificial layer, the first SiO2 layer, and the silicon substrate with a first preset depth downwardly from the top surface of the sacrificial layer according to the first preset pattern so as to form an initial trench parallel to the fin, wherein the initial trench comprises a first trench, a second trench, and a third trench arranged in sequence;
• step S3, filling a first filler in the initial trench until the first filler is flush with the top surface of the sacrificial layer, wherein the first filler comprises SiO2;
• step S4, forming a second preset pattern on a top surface of the first filler, wherein the second preset pattern is located at positions of the first trench and the second trench, sequentially etching the first filler and the silicon substrate with a second preset depth downwardly from the top surface of the first filler according to the second preset pattern so as to form a first initial blind hole;
• step S5, filling a second filler in the first initial blind hole until the second filler is flush with the top surface of the sacrificial layer, removing the sacrificial layer, and the first filler and second filler located within a height range of the sacrificial layer sequentially so as to obtain a second structure, wherein the second filler comprises SiO2;
• step S6, growing a second SiO2 layer on a top surface of the second structure, etching the second SiO2 layer corresponding to a position of the remaining first filler and the second SiO2 layer corresponding to a position of the remaining second filler, etching the remaining first filler to form a target trench, and etching the remaining second filler to form a first target blind hole;
• step S7, filling a third filler in the target trench and the first target blind hole, wherein the third filler is higher than a root of the fin and lower than a top of the fin, filling a fourth filler on a top surface of the third filler until the fourth filler is flush with the second SiO2 layer so as to obtain a third structure, wherein the third filler comprises tungsten and the fourth filler comprises SiO2;
• step S8, forming a third preset pattern on a top surface of the third structure, etching the second SiO2 layer, the fourth filler, and the first SiO2 layer downwardly from the top surface of the third structure according to the third preset pattern until the third filler is exposed, filling a fifth filler in a trench generated by etching until the fifth filler is flush with the second SiO2 layer, so that a fourth structure is obtained, wherein the fifth filler comprises tungsten, and the third preset pattern does not comprise a position corresponding to the first target blind hole;
• and
• step S9, thinning the fourth structure from a side of the silicon substrate until the third filler in the first target blind hole is exposed, so that a self-aligned nanometer through-silicon-via structure is obtained,
• wherein an anisotropic etching selective ratio of a material used in the sacrificial layer to the silicon substrate, the first SiO2 layer, the first filler, and the second filler are less than or equal to a preset ratio, and the preset ratio is 1:10;
• wherein before filling the third filler in the target trench and the first target blind hole in step S7, the method further comprises:
• sequentially growing an electrical isolation layer, a diffusion barrier layer, and an adhesive layer at a bottom and a side wall of the target trench and the first target blind hole.