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CN-121985802-A - Method for processing etched groove and through hole

CN121985802ACN 121985802 ACN121985802 ACN 121985802ACN-121985802-A

Abstract

The invention relates to the technical field of semiconductor manufacturing, and particularly discloses a trench and a processing method after etching of the trench, comprising the following steps of providing a substrate, wherein an interlayer dielectric layer is formed on the surface of the substrate, the etched via and trench are formed in the interlayer dielectric layer, and the bottom of the via is exposed with the surface of a copper interconnection structure; and performing first plasma treatment on the substrate to remove etching byproducts on the surfaces of the through holes, the grooves and the copper interconnection structures, and forming a first carbon-based film on the surfaces of the through holes, the grooves and the copper interconnection structures. According to the method for processing the etched groove and the etched through hole, the second carbon-based film formed on the surfaces of the groove and the etched through hole serves as a protective structure before wet cleaning, the oxygen content of the copper surface is hardly increased even if the groove and the etched through hole are stored in the atmosphere for a long time, the effect of protecting and isolating water vapor is truly achieved, and the problems of damage to a low-dielectric-constant material and oxidation of a front layer metal caused by etching in the prior art are solved.

Inventors

  • JIN WENLIANG
  • ZHANG NIANHENG
  • CAI XIANZHU

Assignees

  • 重庆芯联微电子有限公司

Dates

Publication Date
20260505
Application Date
20251229

Claims (10)

  1. 1. A processing method after etching a groove and a through hole is characterized by comprising the following steps: S1, providing a substrate, wherein an interlayer dielectric layer is formed on the surface of the substrate, a through hole and a groove which are obtained by etching are formed in the interlayer dielectric layer, and the bottom of the through hole is exposed on the surface of a front-layer copper interconnection structure; s2, performing first plasma treatment on the substrate to remove etching byproducts on the surfaces of the through holes, the grooves and the copper interconnection structures, and forming a first carbon-based film on the surfaces of the through holes, the grooves and the copper interconnection structures, wherein process gas of the first plasma treatment comprises CO and N 2 ; S3, performing second plasma treatment on the substrate to reduce copper oxide on the surface of the copper interconnection structure, wherein process gas of the second plasma treatment comprises N 2 and H 2 ; And S4, performing third plasma treatment on the substrate to form a second carbon-based film on the surfaces of the through hole, the groove and the copper interconnection structure, wherein process gas of the third plasma treatment comprises CO and N 2 .
  2. 2. The method of claim 1, wherein steps S1, S2, S3 and S4 are performed sequentially at the same process temperature in the same vacuum chamber.
  3. 3. The post-trench and via etching processing method according to claim 2, wherein: the process temperature was 50 ℃.
  4. 4. The method of claim 1 or 2, wherein the third plasma treatment has a process pressure of 250-300mT, a high frequency (40 MHz) power of 300-400W, a low frequency (13 MHz) power of 0W, a CO flow of 100 sccm, a N 2 flow of 300-500 sccm, and a treatment time of 20-40 seconds.
  5. 5. The method of claim 1, wherein the second carbon-based film has a thickness of 100-200A.
  6. 6. The method of claim 4, wherein the first plasma treatment comprises a process pressure of 100-150 mT, a high frequency (40 MHz) power of 300-400W, a low frequency (13 MHz) power of 50-100W, a CO flow of 100-200 sccm, a N 2 flow of 700-900 sccm, and a treatment time of 20-40 seconds.
  7. 7. The method of claim 6, wherein the second plasma treatment has a process pressure of 250-350mT, a high frequency (40 MHz) power of 300-400W, a low frequency (13 MHz) power of 50-100W, a H 2 flow of 10-20sccm, a N 2 flow of 10-100sccm, and a treatment time of 20-40 seconds.
  8. 8. The method of claim 7, wherein the total duration of the first, second and third plasma treatments is 70-90 seconds.
  9. 9. The method of claim 1, wherein the interlayer dielectric layer comprises a stacked etch stop layer and low dielectric constant material layer.
  10. 10. The method of claim 1, wherein the second carbon-based film is removed by wet cleaning prior to filling the via and trench with copper metal.

Description

Method for processing etched groove and through hole Technical Field The invention relates to the technical field of semiconductor manufacturing, in particular to a method for processing etched grooves and through holes. Background As semiconductor fabrication technology enters deep sub-micron and nano-nodes, copper-low k dual damascene structures become the mainstream interconnect scheme, which forms trenches (vias) and vias (Via) in low dielectric constant dielectric layers by dry etching PET (Post ETCH TREATMENT). However, as shown in FIG. 4, after etching to form the via and trench, the via and trench surfaces are contaminated simultaneously by the two types of residual fluoropolymer (CF_x) first, increasing contact resistance, and the second formed copper oxide (CuO) thin layer, resulting in increased resistance, plating fill defects and reduced electromigration lifetime. Therefore, how to alleviate the damage to the Low dielectric constant (Ultra Low K) material and the oxidation of the front metal Cu after etching becomes a problem that we need to solve at present. Disclosure of Invention The invention aims to provide a method scheme for processing etched grooves and through holes, which is used for passivating the exposed copper surface and solves the problems of damage and front-layer copper metal oxidation caused by the low dielectric constant material generated after etching in the prior art. In order to achieve the above purpose, the invention provides a method for processing etched grooves and through holes, comprising the following steps: S1, providing a substrate, wherein an interlayer dielectric layer is formed on the surface of the substrate, a through hole and a groove which are obtained by etching are formed in the interlayer dielectric layer, and the bottom of the through hole is exposed on the surface of a front-layer copper interconnection structure; s2, performing first plasma treatment on the substrate to remove etching byproducts on the surfaces of the through holes, the grooves and the copper interconnection structures, and forming a first carbon-based film on the surfaces of the through holes, the grooves and the copper interconnection structures, wherein process gas of the first plasma treatment comprises CO and N 2; S3, performing second plasma treatment on the substrate to reduce copper oxide on the surface of the copper interconnection structure, wherein process gas of the second plasma treatment comprises N 2 and H 2; And S4, performing third plasma treatment on the substrate to form a second carbon-based film on the surfaces of the through hole, the groove and the copper interconnection structure, wherein process gas of the third plasma treatment comprises CO and N 2. The steps S1, S2 and S3 are sequentially executed in the same vacuum cavity at the same process temperature. The process temperature was 50 ℃. The specific process parameters of the third plasma treatment are that the process pressure is 250-300mT, the high-frequency (40 MHz) power is 300-400W, the low-frequency (13 MHz) power is 0W, the CO flow is 100 sccm, the N 2 flow is 300-500 sccm, and the treatment time is 20-40 seconds. The thickness value of the second carbon-based film is 100-200A. The specific process parameters of the first plasma treatment are that the process pressure is 100-150mT, the high-frequency (40 MHz) power is 300-400W, the low-frequency (13 MHz) power is 50-100W, the CO flow is 100-200sccm, the N 2 flow is 700-900 sccm, and the treatment time is 20-40 seconds. The specific process parameters of the second plasma treatment are that the process pressure is 250-350mT, the high-frequency (40 MHz) power is 300-400W, the low-frequency (13 MHz) power is 50-100W, the H 2 flow is 10-20sccm, the N 2 flow is 10-100sccm, and the treatment time is 20-40 seconds. The total duration of the first plasma treatment, the second plasma treatment and the third plasma treatment is 70-90 seconds. The interlayer dielectric layer is of a multi-layer structure and comprises an etching stop layer and a low dielectric constant material layer which are stacked. And removing the second carbon-based film by wet cleaning before filling copper metal in the through holes and the grooves. Compared with the prior art, the invention has the beneficial effects that: According to the method for processing the etched groove and the etched through hole, the 100-200A second carbon-based film formed on the surfaces of the groove and the etched through hole is used as a protective structure before wet cleaning, the oxygen content of the copper surface is hardly increased even if the groove and the etched through hole are stored in the atmosphere for a long time, the effect of protecting and isolating water vapor is truly achieved, no residue exists after cleaning, the subsequent seed layer/electroplating is not influenced, and the reliability and the production line compatibility are considered. The method reduces the RC increment