CN1284215C - Nano double phase composite structure Zr-Si-N diffusion barrier material and its preparing process - Google Patents

Abstract

The present invention discloses a Zr-Si-N diffusion blocking layer material with a nanometer biphase composite structure and a preparation technology thereof. The material of the present invention is prepared in the way that a composite target is composed of a Zr sheet and a plurality of Si sheets which have the dimensions of 10mm*10mm*0.7mm and are arranged on the Zr sheet; a Zr-Si-N thin film with the thickness of 90 to 100 nm is deposited on the composite target. The preparation technology of the present invention adopts RF reactive magnetron sputtering and comprises: the composite target composed of the Zr sheet and the Si sheets is taken as a target; the Zr-Si-N thin film is deposited on the composite target in a mixed gas of N2 and Ar. The thin film presents a biphase composite structure composed of ZrN and Si4N3; isodefect concentration of crystal boundaries is obviously reduced, and hyperchannels in which Cu diffuses is reduced; the film can effectively block the diffusion of Cu toward Si basal bodies at the temperature of 850DEGC; therefore, the layer composed of the film is a diffusion blocking layer with good performance.

Description

Nano two-phase composite structure Zr-Si-N diffusion barrier material and its preparation process

technical field

The invention relates to a nano-composite material and its preparation technology, especially a nano-two-phase composite structure Zr-Si-N diffusion barrier material and its preparation process;

Background technique

TiN and TaN have been widely studied and applied as diffusion barrier materials for Cu interconnects in integrated circuits. However, due to the high temperature treatment required in the Cu interconnect manufacturing process, the failure temperature of TiN and TaN diffusion barriers is relatively low, and cannot be easily It can better meet the requirements of integrated circuits for high thermal stability of the diffusion barrier layer. With the in-depth research, it was found that the composite structure film of TiN and TaN with Si added as a diffusion barrier layer can significantly improve the ability to block Cu diffusion. The failure temperatures of Ti-Si-N and Ta-Si-N are increased to 600°C and 650°C, respectively, and the failure is accompanied by the formation of TiSi ₂ and TaSi ₂ phases, respectively. In order to block the diffusion of Cu at a temperature above 650° C. or higher, it is necessary to develop a new material capable of blocking the diffusion barrier layer of Cu at this temperature, which is also the research purpose of the present invention.

Contents of the invention

The object of the present invention is to provide a Zr-Si-N diffusion barrier material capable of blocking Cu diffusion at a temperature above 650° C. and a preparation process thereof. The Zr-Si-N diffusion barrier material is composed of ZrN and The dual-phase composite composed of Si ₄ N ₃ can effectively block the diffusion of Cu.

Since the temperature at which Zr reacts with Si to form _ZrSi2 is 700 °C, which is higher than 650 °C for Ta and 550 °C for Ti, respectively, the Zr-based diffusion barrier layer has more excellent barrier properties. The study found that the ZrN diffusion barrier layer can still effectively block the diffusion of Cu at 800 °C, and the addition of Si can significantly improve the ability of the single-phase nitride diffusion barrier layer to block Cu diffusion. Therefore, the ZrN diffusion barrier layer added with Si should be an excellent diffusion barrier layer. Barrier material.

The technical solution for realizing the present invention is: a Zr-Si-N diffusion barrier material with a nano-two-phase composite structure, a composite target composed of a Zr sheet and several Si sheets placed thereon, and a Zr-Si-N thin film deposited on the surface of the Si sheet ; The deposited Zr-Si-N film is a two-phase composite composed of ZrN and Si ₄ N ₃ .

The preparation process of this material uses the following steps:

1) Select the target material: select a Zr sheet and place several Si sheets with a length×width×thickness of 10mm×10mm×0.7mm on the Zr sheet to form a composite target, and use the Si sheet as the substrate;

2) Thin film deposition: use reactive magnetron sputtering on the composite target in N ₂ /Ar mixed gas to deposit a Zr-Si-N film with a thickness of 90-100 nm; the film is composed of ZrN and Si ₄ N ₃ The two-phase compound; the reactive magnetron sputtering uses a radio frequency power supply, applies a negative bias voltage of 50-200V to the substrate, the sputtering pressure is 0.3Pa, and the _N2 partial pressure is 0.06-0.09Pa.

The Zr-Si-N film deposited by the preparation process of the present invention is a dual-phase composite structure composed of ZrN and Si ₄ N ₃ , structural defects such as grain boundaries in the film are significantly reduced, and the fast channel for Cu to diffuse in it is reduced, obviously The performance of blocking Cu diffusion is improved, and the diffusion of Cu can still be effectively blocked at 850°C.

Detailed ways

Example 1, place 4 Si slices of length x width x thickness 10mm x 10mm x 0.7mm on a Zr slice with a diameter x length of Φ75 x 6mm, using a single crystal Si slice as the substrate in a N ₂ /Ar mixed gas The Zr-Si-N thin film was deposited by reactive magnetron sputtering. The back vacuum of the vacuum chamber was 2×10 ^-5 Pa, a radio frequency power supply was used, a 50V negative bias was applied to the substrate, and the total flow rate of the sputtering gas was 20 sccm. The sputtering pressure is 0.3Pa, the partial pressure of _N2 is 0.06Pa, the partial pressure of Ar is 0.24Pa, the deposition time is 20min, and the thickness of the deposited Zr-Si-N film is 95-100nm. The film is a composite composed of amorphous ZrN and Si ₄ N ₃ , and the diffusion of Cu in it is still not obvious after annealing at 850°C for 1 hour, which can effectively block the diffusion of Cu.

Example 2, 4 pieces of Si slices of length x width x thickness 10mm x 10mm x 0.7mm are placed on the Zr slice with diameter x length of Φ75 x 6mm, using single crystal Si slices as the substrate in N ₂ /Ar mixed gas The Zr-Si-N thin film was deposited by reactive magnetron sputtering. The back vacuum of the vacuum chamber was 2×10 ^-5 Pa, a radio frequency power supply was used, a negative bias voltage of 100V was applied to the substrate, and the total flow rate of the sputtering gas was 20 sccm. The sputtering pressure is 0.3Pa, the partial pressure of _N2 is 0.06Pa, the partial pressure of Ar is 0.24Pa, the deposition time is 20min, and the thickness of the deposited Zr-Si-N film is 95-100nm. The film is a composite composed of nanocrystalline ZrN and amorphous Si ₄ N ₃ , the grain diameter is about 6nm, the diffusion of Cu in it is still not obvious after annealing at 850°C for 1 hour, and it has excellent performance of blocking Cu diffusion .

Example 3, 4 pieces of Si slices of length x width x thickness 10mm x 10mm x 0.7mm are placed on a Zr sheet with a diameter x length of Φ75 x 6mm. The single crystal Si slice is used as the substrate in a N ₂ /Ar mixed gas. The Zr-Si-N thin film was deposited by reactive magnetron sputtering. The back low vacuum degree of the vacuum chamber was 2×10 ^-5 Pa, a radio frequency power supply was used, a negative bias voltage of 200V was applied to the substrate, and the total flow rate of the sputtering gas was 20 sccm. The sputtering pressure is 0.3Pa, the partial pressure of _N2 is 0.06Pa, the partial pressure of Ar is 0.24Pa, the deposition time is 20min, and the thickness of the deposited Zr-Si-N film is 95-100nm. The thin film is a compound composed of nanocrystalline ZrN and amorphous Si ₄ N ₃ , at this time, the crystal phase of ZrN increases, and the grain diameter is about 10nm. After annealing at 850°C for 1 hour, Cu diffuses in it, but the diffusion of Cu still does not pass through the diffusion barrier layer, which can still effectively block the diffusion of Cu.

Example 4, place 4 Si slices of length x width x thickness 10mm x 10mm x 0.7mm on a Zr slice with a diameter x length of Φ75 x 6mm, using a single crystal Si slice as the substrate in a N ₂ /Ar mixed gas The Zr-Si-N thin film was deposited by reactive magnetron sputtering. The back low vacuum degree of the vacuum chamber was 2×10 ^-5 Pa, a radio frequency power supply was used, a negative bias voltage of 200V was applied to the substrate, and the total flow rate of the sputtering gas was 20 sccm. The sputtering pressure is 0.3Pa, the partial pressure of _N2 is 0.09Pa, the partial pressure of Ar is 0.24Pa, the deposition time is 20min, and the thickness of the deposited Zr-Si-N film is 95-100nm. The thin film is a compound composed of nanocrystalline ZrN and crystalline Si ₄ N ₃ , and the grain diameter is about 20nm. After annealing at 850°C for 1 hour, Cu diffuses obviously in it, but the diffusion of Cu still does not reach the Si matrix, which can still block the diffusion of Cu.

Example 5, put 6 Si slices of length x width x thickness 10mm x 10mm x 0.7mm on a Zr slice with a diameter x length of Φ75 x 6mm, using a single crystal Si slice as the substrate in a N ₂ /Ar mixed gas The Zr-Si-N thin film was deposited by reactive magnetron sputtering. The back vacuum of the vacuum chamber was 2×10 ^-5 Pa, a radio frequency power supply was used, a negative bias voltage of 100V was applied to the substrate, and the total flow rate of the sputtering gas was 20 sccm. The sputtering pressure is 0.3Pa, the partial pressure of _N2 is 0.06Pa, the partial pressure of Ar is 0.24Pa, the deposition time is 20min, and the thickness of the deposited Zr-Si-N film is 95-100nm. The film is a composite composed of amorphous ZrN and Si ₄ N ₃ . After annealing at 850°C for 1 hour, there is no significant diffusion of Cu in it, which can effectively block the diffusion of Cu.

Compared with existing Ti-Si-N and Ta-Si-N diffusion barrier layers, the Zr-Si-N thin film of the present invention has: excellent resistance to Cu diffusion; high thermal stability; incompatibility at high temperatures Si matrix reacts and fails, which is a kind of diffusion barrier layer with application prospect.

Claims (4)

1, a kind of nanometer two-phase composite construction Zr-Si-N diffusion barrier material is characterized in that, this material is by the Zr sheet and go up the composite target that the some Si sheets of placement are formed, deposition Zr-Si-N film on Si sheet surface; The Zr-Si-N film that is deposited is ZrN and Si ₄N ₃The two-phase compound of forming.

2, a kind of preparation technology of nanometer two-phase composite construction Zr-Si-N diffusion barrier material is characterized in that this preparation technology adopts following steps:

1) choose target: choosing the Zr sheet and place some lengths of a film * wide * thickness on the Zr sheet is that the Si sheet of 10mm * 10mm * 0.7mm is formed composite target, with the Si sheet as matrix;

2) carry out thin film deposition: with composite target at N ₂Use reaction magnetocontrol sputtering in the/Ar mist, it is the Zr-Si-N film of 90-100nm that deposition generates thickness.

3, the preparation technology of nanometer two-phase composite construction Zr-Si-N diffusion barrier material according to claim 2 is characterized in that: the Zr-Si-N film that deposition generates is by ZrN and Si ₄N ₃The two-phase compound of forming.

4, the preparation technology of nanometer two-phase composite construction Zr-Si-N diffusion barrier material according to claim 2 is characterized in that: reaction magnetocontrol sputtering adopts radio-frequency power supply, and matrix is applied the back bias voltage of 50V-200V, and sputtering pressure is 0.3Pa, N ₂Dividing potential drop is 0.06-0.09Pa.