Plasma enhanced physical vapor deposition method

Abstract

The invention provides a plasma enhanced physical vapor deposition method, which comprises the following steps of: (1) a, sequentially forming a high-resistance metal oxide and a metal film protection layer on the surface of a metal shielding piece, and generating negative potential; or b, depositing a metal film protection layer on the insulating shielding piece through a magnetron sputtering method, and generating negative potential; (2) preparing a metal film through magnetron sputtering: transmitting the substrate to a carrying table, lifting an annular metal baffle plate into a shielding piece, introducing a certain flow of argon to form glow discharge plasmas, and colliding the plasmas with sputtered metal atoms to generate a large number of metal ions to form the metal film on the substrate; and (3) charges on the surface of the shielding piece in the PVD vacuum cavity are eliminated and initialized. According to the method, the high-resistance metal oxide and the metal film protection layer are formed on the surface of the metal shielding piece or the metal film protection layer is formed on the insulating shielding piece, and the negative potential is generated, so that the plasma density during metal film sputtering can be enhanced, and the step coverage rate of the metal film is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a plasma enhanced physical vapor deposition method. Background Art

[0002] Magnetic fields play an extremely important role in plasma technology, especially high-density plasma technology. In many important technical application fields, the generation and control of plasma are closely related to the magnetic field. Many plasma systems need to be equipped with specially designed magnetic structures to enhance and control the plasma density, distribution and other properties and processing parameters (such as sputtering rate, etching rate, film step coverage, etc.). The basic mechanism of the effect of magnetic field on plasma lies in the Lorentz force. Dutch physicist Lorentz first pointed out that charged particles moving in a magnetic field will always be subject to a magnetic field force. The direction of the force is perpendicular to the plane formed by the magnetic field and the particle velocity. The magnitude of the force is proportional to the particle charge (q), velocity, magnetic induction intensity and the sine function of the angle between the latter two. The Lorentz force can be expressed as the vector product of the charged particle velocity (1) and the magnetic induction intensity (B), as shown in the following formula: F=qv×B The direction of the Lorentz force can be determined by the screw rule. For the same magnetic field and particle velocity, the Lorentz forces on positive and negative charged particles are opposite in direction. Therefore, the magnetic field can be used to separate electrons and ions in a plasma flow. For example, the particle velocity vector can be decomposed into two components perpendicular to and parallel to the magnetic field direction: v = v ⊥ + v || , the vertical component contributes to the Lorentz force. The Lorentz force causes charged particles to perform cyclotron or spiral motion with the magnetic field as the axis. Based on the Lorentz force and the circular motion equation, the radius and frequency of the cyclotron motion of charged particles can be calculated. The cyclotron radius depends on the magnetic induction intensity, the particle mass (m), the charge, and the particle velocity component perpendicular to the magnetic field (v ⊥ ).

[0003] r = mv ⊥ / qB Since the electrons and ions in the plasma are independent and movable, both are affected by the Lorentz force of the external magnetic field. The electrons and positive ions have equal charges and are affected by the Lorentz forces of opposite directions and equal magnitudes in the magnetic field. However, due to the large mass difference between the two, the radius of curvature of the electron motion deflection in the magnetic field is significantly smaller than that of the ions. Taking the argon ions and electrons in the magnetic field as an example, their speed can be calculated by their kinetic energy. If it is assumed that the kinetic energy of both is 100 eV and the magnetic induction intensity is 100 Gs, it can be estimated that the radius of curvature of the electron is 0.3 cm and that of the argon ion is 66 cm. This shows that the deflection of ion motion caused by the magnetic field is very small, while the motion of the electron changes greatly under the action of the magnetic field. Although the Lorentz force does not do work on the electrons and cannot increase the electron energy, the spiral motion it causes greatly increases the electron motion path, increases the probability of collision with neutral atoms, and significantly increases the ionization rate and plasma density. The high-density plasma ionizes a large number of sputtered metal atoms (M+e=M + +2e). If a radio frequency power source is applied to the substrate to generate a negative bias voltage, the metal ions are guided to be deposited on the silicon wafer in a directional manner, thereby increasing the step coverage of the film.

[0004] Most of the existing methods of increasing plasma density in magnetron sputtering technology are through the design of magnetrons. In addition to controlling plasma distribution and separating charges, the magnetic field also has the function of increasing plasma density. According to different application requirements, magnets with different structures are designed and placed, and non-uniform magnetic fields can be used to gather and constrain plasma. The application of a non-uniform magnetic field with a weak middle and strong ends can bind charged particles in it. This non-uniform magnet structure is often called a "magnetic mirror", meaning that the moving charged particles can be "reflected" back to the weak magnetic field area in the middle by the strong magnetic field areas on both sides, just like a mirror reflecting light. However, the magnetic field strength of the magnetron itself is very limited, and the average magnetic field strength of the target surface is about 400Gs. This plasma-enhanced magnetron design leads to a large difference in the strength of the magnetic field in the middle and at both ends, poor target etching uniformity, low target utilization, and film uniformity will also be affected. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a plasma enhanced physical vapor deposition method. The present invention first forms a high-resistance metal oxide on the surface of a metal shield in a PVD equipment cavity, forms a metal film protective layer on the high-resistance metal oxide, and generates a negative potential, or deposits a metal film protective layer of a certain thickness on an insulating shield by a magnetron sputtering method, generates a certain negative potential, and then sputters a metal film, which can be filled into micropores at the same time. By this method, the plasma density during the sputtering of the metal film can be enhanced, and the step coverage of the metal film can be significantly improved.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiment of the present invention is: a plasma enhanced physical vapor deposition method, comprising the following steps: (1) a. forming a high-resistance metal oxide on the surface of the shielding member in the cavity, forming a metal film protective layer on the high-resistance metal oxide, and generating a negative potential, wherein the shielding member is a metal shielding member; or b. Depositing a metal film protective layer of a certain thickness on the shielding member by a magnetron sputtering method and generating a certain negative potential, wherein the shielding member is an insulating shielding member; (2) Preparation of metal film by magnetron sputtering: The substrate is transferred to the carrier, the annular metal baffle is lifted into the shield, and a certain flow of argon gas is introduced to form a glow discharge plasma. The electrons accumulated on the surface of the shield in the PVD vacuum chamber will inhibit the electrons from continuing to move to the inner wall shield surface during subsequent sputtering. The electron density is enhanced, and the electrons collide with argon atoms to produce more argon positive ions and electrons, and the plasma density is increased. The plasma with increased density collides with the sputtered metal atoms to produce a large number of metal ions. The carrier generates a negative bias voltage due to the application of RF power, which guides the metal ions to accelerate and directional deposition on the substrate to form a metal film. (3) Eliminate and initialize the charge on the surface of the shield in the PVD vacuum chamber; The shielding member in steps (2) and (3) is a metal shielding member or an insulating shielding member, and the shielding member in steps (2) and (3) is of the same type as the shielding member in step (1).

[0007] Furthermore, case a in step (1) includes the following steps: (1.1) Forming high-resistance metal oxide: The pre-sputtered substrate is transferred to a PVD vacuum chamber, and a certain flow rate and ratio of argon-oxygen mixed gas is introduced into the PVD vacuum chamber. The argon gas is ionized to form a glow discharge plasma, wherein the argon positive ions are accelerated by the cathode target to bombard the target material to produce metal atoms, and the metal atoms react with oxygen to form metal oxides, and high-resistance metal oxides are formed on the surface of the shield in the chamber, wherein the thickness of the high-resistance metal oxide is greater than 100 nm, and the resistivity is greater than 1000 μΩ·cm; (1.2) Forming a metal film protective layer on the high-resistance metal oxide and generating a negative potential: After a high-resistance metal oxide film is formed on the surface of the shield in the cavity in step (1.1), a metal film protective layer is further formed on the high-resistance metal oxide by magnetron sputtering. During magnetron sputtering, electrons in the plasma are accelerated away from the cathode target and migrate to the baffle and the shield in the PVD vacuum chamber, forming a negative potential on the surface of the shield, with a potential of -50~-5V.

[0008] Furthermore, case b in step (1) includes the following steps: The pre-sputtered substrate is transferred to the PVD vacuum chamber, and a certain flow of argon gas is introduced into the PVD vacuum chamber. The argon gas is ionized to form a glow discharge plasma, in which the positive argon ions are accelerated by the cathode target to bombard the target material to produce metal atoms, and a metal film protective layer of a certain thickness is formed on the surface of the shield in the chamber. The electrons in the plasma are accelerated away from the cathode target and migrate to the baffle and the shield in the vacuum chamber, forming a negative potential on the surface of the shield, and the potential is -50~-5V.

[0009] Furthermore, in step (1.1), the argon flow rate in the argon-oxygen mixed gas is 20-100 sccm, the oxygen flow rate is 10-100 sccm, the chamber reaction pressure is 1.8-20 mTorr, the target input power is 500-6000 W, and the sputtering time is 5-20 min.

[0010] Furthermore, when the substrate is pre-sputtered, the distance between the target and the substrate stage is 150-450 mm, the substrate temperature is 25-300° C., and the vacuum degree of the PVD vacuum chamber is maintained at 5.0×10 -8 Torr or less, sputtering power 1000-3000W, pre-sputtering target for 1-3min.

[0011] Furthermore, the target material is one of a titanium target, a tantalum target, a copper target, a nickel target, a tungsten target, a titanium-tungsten alloy target and an Ag target.

[0012] Furthermore, when forming the metal film protective layer, the argon gas flow rate is 20-60sccm, the chamber reaction pressure is 1.2-3.6mTorr, the target input power is 1000-10000W, and the sputtering time is 1-5min.

[0013] Furthermore, when the metal film is prepared by magnetron sputtering in step (2), the argon gas flow rate is 20-60 sccm, the chamber reaction pressure is 1.2-3.6 mTorr, the target sputtering power is set to 1000-10000 W, the stage input RF power is set to 50-500 W, the RF frequency is 2-27.12 MHz, and the sputtering time is 1-5 min.

[0014] Furthermore, the material, type and purity of the annular metal baffle in step (2) are the same as those of the target material, and the lifting and lowering of the annular metal baffle is controlled by a cylinder; The annular metal baffle is used to prevent the positive ions in the plasma from bombarding the insulating metal oxide film on the shield surface under the pulling effect of the negative potential on the shield surface, thereby avoiding the generation of impurities and neutralizing the charge on the shield surface.

[0015] Furthermore, in step (3), during the process of the substrate stage descending from the process position to the initial transfer position, the charge is eliminated by the annular metal baffle plate in physical contact with the spring installed at the bottom of the PVD vacuum chamber, thereby maintaining the inter-sheet stability of the step coverage; When the vertical distance between the upper edge of the annular metal baffle and the baffle is 3-5 mm, it is the initial position of the annular metal baffle; When the annular metal baffle moves upward to a point where the vertical distance between the upper edge and the target surface is 3-5 mm, it is the process position of the annular metal baffle.

[0016] The technical solution provided by the embodiment of the present invention has the following beneficial effects: The present invention first forms a high-resistance metal oxide on the surface of a metal shield in a cavity of a PVD sputtering device, forms a metal film protective layer on the high-resistance metal oxide, and generates a negative potential, or deposits a metal film protective layer of a certain thickness on the insulating shield by a magnetron sputtering method, and generates a certain negative potential, and then sputters the metal film. The film can also be filled into the micropores. Through this method, the plasma density of the metal film during sputtering can be enhanced, and the step coverage of the metal film can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the PVD sputtering equipment chamber in an embodiment of the present invention.

[0018] Figure 2 Step coverage diagram of the metal titanium film in the micropores in Example 1 of the present invention.

[0019] Figure 3 Step coverage diagram of the metal titanium film in the micropores in Example 2 of the present invention.

[0020] Figure 4 Step coverage diagram of the metal titanium film in the micropores in the comparative example of the present invention.

[0021] Explanation of the reference numerals: 1- shielding member; 2- annular metal baffle; 3- cylinder; 4- guide rod; 5- spring; 6- baffle; 7- track trolley. DETAILED DESCRIPTION

[0022] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "inside, outside", "up, down", "left, right", etc. are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention.

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] like Figure 1 As shown, the shield 1 is located above the substrate in the PVD vacuum chamber to prevent the inner wall of the chamber from being contaminated during physical vapor deposition, and can be replaced and cleaned when the maintenance cycle is reached.

[0025] The annular metal baffle 2 is raised and lowered by the cylinder 3. When the vertical distance between the upper edge of the annular metal baffle 2 and the baffle 6 is 3-5 mm, it is the initial position of the annular metal baffle 2; when the annular metal baffle 2 moves upward to a vertical distance between the upper edge and the target surface of 3-5 mm, it is the process position of the annular metal baffle 2.

[0026] The annular metal baffle 2 is sleeved on the guide rod 4 through a sleeve. When the cylinder 3 controls the lifting and lowering movement of the annular metal baffle 2, the guide rod 4 provides a guiding function.

[0027] The vertical distance between the baffle plate 6 on the left and the upper surface of the stage is 5-30 mm, and it is driven by the track trolley 7 to move horizontally to shield the substrate to avoid contamination of the substrate surface when the metal oxide film is plated. The bottom of the spring 5 is installed at the bottom of the PVD vacuum chamber to achieve grounding. When the annular metal baffle 2 descends and contacts the spring 5, discharge can be completed to avoid damage to the substrate.

[0028] Example 1 A plasma enhanced physical vapor deposition method comprises the following steps: (1) Pre-sputtering: Based on SJI-SEMI's Depomerits P1 88+ Pro PVD equipment, a titanium target with a target purity of 99.999% was selected. The distance between the target and the wafer carrier was 250 mm. The substrate temperature was set to 300 °C and the chamber background vacuum was maintained at 1.0 × 10 -8 Torr, using 1000W sputtering power and pre-sputtering the target for 3min; (2) Formation of insulating metal oxide: The wafer is transferred to a PVD vacuum chamber, and an argon-oxygen mixed gas with an argon flow rate of 20 sccm and an oxygen flow rate of 50 sccm is introduced. The chamber reaction pressure is 3.6 mTorr, the target input power is 3000 W, and the sputtering time is 10 min. The argon gas is ionized to form a glow discharge plasma, in which the argon positive ions are accelerated by the cathode target to bombard the target to produce metal atoms. The metal atoms react with oxygen to form metal oxides, and high-resistance metal oxides are formed on the surface of the metal shield in the chamber. The high-resistance metal oxide is a titanium oxide film with a thickness of 200 nm and a resistivity of 10 4 μΩ·cm; (3) Forming a metal film protective layer and generating a certain negative potential: After a high-resistance metal oxide film is formed on the surface of the metal shield in the cavity in step (1), argon gas is continuously introduced at a flow rate of 30 sccm, the cavity reaction pressure is 1.8 mTorr, the target input power is 10000 W, and the sputtering time is 1 min. A metal film protective layer is formed on the surface of the metal shield in the cavity by magnetron sputtering. The metal film protective layer is a titanium film with a thickness of 50 nm. During magnetron sputtering, electrons in the plasma are accelerated away from the cathode target and migrate to the baffle and the shield in the PVD vacuum cavity, forming a negative potential on the surface of the shield, with a potential of -10 V. (4) Preparation of metal film by magnetron sputtering: The wafer is transferred to the carrier, and the annular metal baffle (the metal material type and purity are the same as the target material) is lifted into the metal shield. Argon gas with a flow rate of 30 sccm is introduced to form a glow discharge plasma. The chamber reaction pressure is 1.8 mTorr, the target sputtering power is set to 9000 W, the carrier input RF power is set to 100 W, the RF frequency is 13.56 MHz, and the sputtering time is 1.5 min. The electrons accumulated on the surface of the metal shield in the vacuum chamber will inhibit the electrons from continuing to move to the surface of the inner wall metal shield during subsequent sputtering. The electron density is enhanced, and the electrons collide with argon atoms to produce more argon positive ions and electrons, which increases the plasma density. The plasma with increased density collides with the sputtered metal atoms to produce a large number of metal ions. The carrier generates a negative bias voltage due to the application of RF power, which will guide the metal ions to accelerate the directional deposition on the silicon wafer to form a metal titanium film, thereby improving the step coverage of the film. The annular metal baffle can prevent the positive ions in the plasma from bombarding the insulating metal oxide film on the surface of the metal shield under the pulling effect of the negative potential on the surface of the metal shield, thereby avoiding the generation of impurities and neutralizing the charge on the surface of the metal shield. (5) Eliminate and initialize the charge on the surface of the metal shield in the PVD vacuum chamber: When the substrate carrier is lowered from the process position to the initial transfer position, the charge is eliminated after the annular metal shield physically contacts the spring installed at the bottom of the PVD vacuum chamber, thereby maintaining the inter-sheet stability of the step coverage.

[0029] Example 2 A plasma enhanced physical vapor deposition method comprises the following steps: (1) Pre-sputtering: Based on SJI-SEMI's Depomerits P188+ Pro PVD equipment, a titanium target with a target purity of 99.999% was selected. The distance between the target and the wafer carrier was 250 mm. The substrate temperature was set to 300 °C and the chamber background vacuum was maintained at 1.0 × 10 -8 Torr, using 1000W sputtering power and pre-sputtering the target for 3min; (2) Forming a metal film protective layer and generating a certain negative potential: introducing argon gas with a flow rate of 30 sccm into the PVD vacuum chamber to form a glow discharge plasma, the chamber reaction pressure is 1.8 mTorr, the target input power is 10000 W, the sputtering time is 1 min, and a metal film protective layer is formed on the surface of the insulating shield in the chamber by magnetron sputtering. The metal film protective layer uses a titanium film with a thickness of 50 nm; (3) Preparation of metal film by magnetron sputtering: The wafer is transferred to the carrier, and the annular metal baffle (the metal material type and purity are the same as the target material) is lifted into the insulating shield. Argon gas with a flow rate of 30 sccm is introduced to form a glow discharge plasma. The cavity reaction pressure is 1.8 mTorr, the target sputtering power is set to 9000 W, the carrier input RF power is set to 100 W, the RF frequency is 13.56 MHz, and the sputtering time is 1.5 min. The electrons accumulated on the surface of the insulating shield in the vacuum chamber will inhibit the electrons from continuing to move to the surface of the inner wall insulating shield during subsequent sputtering. The density is enhanced, and the collision between electrons and argon atoms produces more argon positive ions and electrons, which increases the density of the plasma. The plasma with increased density collides with the sputtered metal atoms to produce a large number of metal ions. The carrier generates a negative bias voltage due to the application of RF power, which guides the metal ions to accelerate and directional deposition on the silicon wafer to form a metal titanium film, thereby improving the step coverage of the film. Among them, the annular metal baffle can prevent the positive ions in the plasma from bombarding the insulating metal oxide film on the surface of the insulating shield under the pulling effect of the negative potential on the surface of the insulating shield, thereby avoiding the generation of impurities and the neutralization of the charge on the surface of the insulating shield. (4) Eliminating and initializing the charge on the surface of the insulating shield in the PVD vacuum chamber: During the process of the substrate carrier descending from the process position to the initial transfer position, the charge is eliminated after the annular metal baffle physically contacts the spring installed at the bottom of the PVD vacuum chamber, thereby maintaining the inter-sheet stability of the step coverage.

[0030] Comparative Example 1 A plasma physical vapor deposition method comprises the following steps: (1) Pre-sputtering: Based on SJI-SEMI's Depomerits P188+ Pro PVD equipment, a titanium target with a target purity of 99.999% was selected. The distance between the target and the wafer carrier was 250 mm. The substrate temperature was set to 300 °C and the chamber background vacuum was maintained at 1.0 × 10 -8 Torr, using 1000W sputtering power and pre-sputtering the target for 3min; (2) Preparation of metal thin film by magnetron sputtering: argon gas with a flow rate of 30 sccm was introduced to form a glow discharge plasma, the chamber reaction pressure was 1.8 mTorr, the target sputtering power was set to 9000 W, the stage input RF power was set to 100 W, the RF frequency was 13.56 MHz, and the sputtering time was 1.5 min to obtain a metal titanium film.

[0031] The distribution of the thickness of the titanium film in the micropores or grooves of the substrate was observed under a scanning electron microscope. The step coverage is defined as the ratio of the sidewall or bottom film thickness to the top plane film thickness. The sidewall step coverage is calculated by taking the average value of the sidewall film thickness on both sides. The calculated step coverage is shown in Tables 1 and Figure 2 , 3 、4.

[0032] Table 1 Comparison of film step coverage in Example 1 and Comparative Example 1 Combination Figure 2 , Figure 3 , Figure 4 From Table 1, we can see that the thickness of the sputtered film in the middle and bottom of the sidewall of Comparative Example 1 is too thin, with a coverage rate of about 10%. However, when the plasma enhanced physical vapor deposition method of the present application is used, the overall coverage rate of the film step is significantly higher than that of the ordinary physical vapor deposition method, the sidewall is relatively continuous, the sidewall coverage rate exceeds 18%, and the bottom coverage rate exceeds 30%.

[0033] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A plasma enhanced physical vapor deposition method, characterized in that: The following steps are involved: (1) a. forming a high-resistance metal oxide on the surface of the shielding member in the cavity, forming a metal film protective layer on the high-resistance metal oxide, and generating a negative potential, wherein the shielding member is a metal shielding member; or b. Depositing a metal film protective layer of a certain thickness on the shielding member by a magnetron sputtering method and generating a certain negative potential, wherein the shielding member is an insulating shielding member; (2) Preparation of metal film by magnetron sputtering: The substrate is transferred to the carrier, the annular metal baffle is lifted into the shield, and a certain flow of argon gas is introduced to form a glow discharge plasma. The electrons accumulated on the surface of the shield in the PVD vacuum chamber will inhibit the electrons from continuing to move to the inner wall shield surface during subsequent sputtering. The electron density is enhanced, and the electrons collide with argon atoms to produce more argon positive ions and electrons, and the plasma density is increased. The plasma with increased density collides with the sputtered metal atoms to produce a large number of metal ions. The carrier generates a negative bias voltage due to the application of RF power, which guides the metal ions to accelerate and directional deposition on the substrate to form a metal film. (3) Eliminate and initialize the charge on the surface of the shield in the PVD vacuum chamber; The shielding member in steps (2) and (3) is a metal shielding member or an insulating shielding member, and the shielding member in steps (2) and (3) is of the same type as the shielding member in step (1).

2. The plasma enhanced physical vapor deposition method according to claim 1, characterized in that: Case a in step (1) includes the following steps: (1.1) Forming high-resistance metal oxide: The pre-sputtered substrate is transferred to a PVD vacuum chamber, and a certain flow rate and ratio of argon-oxygen mixed gas is introduced into the PVD vacuum chamber. The argon gas is ionized to form a glow discharge plasma, wherein the argon positive ions are accelerated by the cathode target to bombard the target material to produce metal atoms, and the metal atoms react with oxygen to form metal oxides, and high-resistance metal oxides are formed on the surface of the shield in the chamber, wherein the thickness of the high-resistance metal oxide is greater than 100 nm, and the resistivity is greater than 1000 μΩ·cm; (1.2) Forming a metal film protective layer on the high-resistance metal oxide and generating a negative potential: After a high-resistance metal oxide film is formed on the surface of the shield in the cavity in step (1.1), a metal film protective layer is further formed on the high-resistance metal oxide by magnetron sputtering. During magnetron sputtering, electrons in the plasma are accelerated away from the cathode target and migrate to the baffle and the shield in the PVD vacuum chamber, forming a negative potential on the surface of the shield, with a potential of -50~-5V.

3. The plasma enhanced physical vapor deposition method according to claim 1, characterized in that: Case b in step (1) includes the following steps: The pre-sputtered substrate is transferred to the PVD vacuum chamber, and a certain flow of argon gas is introduced into the PVD vacuum chamber. The argon gas is ionized to form a glow discharge plasma, in which the positive argon ions are accelerated by the cathode target to bombard the target material to produce metal atoms, and a metal film protective layer of a certain thickness is formed on the surface of the shield in the chamber. The electrons in the plasma are accelerated away from the cathode target and migrate to the baffle and the shield in the vacuum chamber, forming a negative potential on the surface of the shield, and the potential is -50~-5V.

4. The plasma enhanced physical vapor deposition method according to claim 2, characterized in that: In step (1.1), the argon flow rate in the argon-oxygen mixed gas is 20-100 sccm, the oxygen flow rate is 10-100 sccm, the chamber reaction pressure is 1.8-20 mTorr, the target input power is 500-6000 W, and the sputtering time is 5-20 min.

5. The plasma enhanced physical vapor deposition method according to claim 2 or 3, characterized in that: When the substrate is pre-sputtered, the distance between the target and the substrate stage is 150-450 mm, the substrate temperature is 25-300 ° C, and the vacuum degree of the PVD vacuum chamber is maintained at 5.0×10 -8 Torr or less, sputtering power 1000-3000W, pre-sputtering target for 1-3min.

6. The plasma enhanced physical vapor deposition method according to claim 2 or 3, characterized in that: The target material is one of a titanium target, a tantalum target, a copper target, a nickel target, a tungsten target, a titanium-tungsten alloy target and an Ag target.

7. The plasma enhanced physical vapor deposition method according to claim 2 or 3, characterized in that: When forming the metal film protective layer, the argon gas flow rate is 20-60sccm, the chamber reaction pressure is 1.2-3.6mTorr, the target input power is 1000-10000W, and the sputtering time is 1-5min.

8. The plasma enhanced physical vapor deposition method according to claim 1, characterized in that: When the metal film is prepared by magnetron sputtering in step (2), the argon gas flow rate is 20-60sccm, the chamber reaction pressure is 1.2-3.6mTorr, the target sputtering power is set to 1000-10000W, the stage input RF power is set to 50-500W, the RF frequency is 2-27.12MHz, and the sputtering time is 1-5min.

9. The plasma enhanced physical vapor deposition method according to claim 1, characterized in that: The material, type and purity of the annular metal baffle in step (2) are the same as those of the target material, and the lifting and lowering of the metal baffle is controlled by a cylinder; The annular metal baffle is used to prevent the positive ions in the plasma from bombarding the insulating metal oxide film on the shield surface under the pulling effect of the negative potential on the shield surface, thereby avoiding the generation of impurities and neutralizing the charge on the shield surface.

10. The plasma enhanced physical vapor deposition method according to claim 1, characterized in that: In step (3), when the substrate stage is lowered from the process position to the initial transfer position, the charge is eliminated by the annular metal baffle plate in physical contact with the spring installed at the bottom of the PVD vacuum chamber, thereby maintaining the inter-sheet stability of the step coverage; When the vertical distance between the upper edge of the annular metal baffle and the baffle is 3-5 mm, it is the initial position of the annular metal baffle; When the annular metal baffle moves upward to a point where the vertical distance between the upper edge and the target surface is 3-5 mm, it is the process position of the annular metal baffle.

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