CN215209603U - Ion-assisted, tilted sputtering PVD system - Google Patents

Abstract

The utility model discloses an ion-assisted and inclined sputtering PVD system, which comprises a chamber, wherein a plasma source, a target bracket and a substrate objective table are arranged in the chamber, the front periphery of the substrate carrying table is provided with a gas spraying unit which comprises a gas spraying ring, the middle of the substrate carrying table corresponding to the gas spraying ring is used for placing a substrate, the gas spraying unit also comprises a plurality of spray holes which are uniformly distributed along the circumference at the inner side of the gas spraying ring, the gas injection ring is provided with an air passage communicated with the injection holes, the utility model is provided with a gas spraying unit which can be used for injecting processing gas such as oxygen, to promote chemical reactions between the process gas and particles sputtered from the target during sputter deposition, the orifices may be uniformly distributed along the length of the gas tube so that the chemical reactions may proceed substantially uniformly across the surface of the wafer.

Description

Ion-assisted, tilted sputtering PVD system

Technical Field

The utility model belongs to film physical vapor deposition system field, more specifically the PVD system that relates to an ion is supplementary, slope is sputtered that says so.

Background

Sputter deposition systems can be used to deposit thin films of various materials on various substrates (e.g., Si substrates). It can be widely applied to a wide variety of industrial fields including, for example, semiconductors, magnetic storage, optical systems, and micro-electro-mechanical systems (MEMS). The material to be deposited can be almost any solid material of metal, semiconductor, insulator, etc., among which oxides, such as aluminum oxide, zinc oxide, tin oxide or titanium dioxide, etc., are contained. By way of example, the deposition system may utilize a plasma generated from an inert gas (e.g., Ar, etc.) to sputter the target material. Atoms (or particles including atoms) of the target material can be ionized and bombarded by high-energy Ar gas plasma accelerated by electric and magnetic fields, and subsequently attached to the surface of the substrate.

In the sputtering process, besides the inert gas (such as Ar gas), a reactive gas (such as oxygen, nitrogen, etc.) may be added to form reactive sputtering, i.e., metal atoms bombarded from the surface of the metal target react with the reactive gas introduced into the chamber to form an oxide, a nitride, etc. before being deposited on the surface of the substrate, and then the oxide, the nitride, etc. are attached to the surface of the substrate.

In the reactive sputtering process, sputtering atoms need to perform chemical reaction of oxidation or nitridation in the cavity, so that it is important to provide a proper amount of stable and uniform reaction gas. The distribution of the reaction gas in the cavity is not very uniform, if the reaction gas inlet is too close to the target, the reaction gas is usually too much in the surface area of the target, so that the phenomenon of target poisoning is generated, electric sparks (arc) are frequently generated, and the sputtering process is possibly interrupted; meanwhile, in the surface area of the substrate, because the reaction gas is insufficient, the metal atoms can not fully react with the reaction gas, and the goal of depositing oxide and nitride can not be achieved.

Meanwhile, the deposition rate of oxide by sputter deposition and reactive sputter deposition is usually not high (2A/sec/kW), so a method of increasing the concentration of gas ions during sputtering is often adopted to increase the sputtering rate, for example, a magnetron (magnetron sputtering), an Inductively Coupled Plasma (ICP) method, etc. is added behind the target.

In addition, due to the common sputtering deposition system, the surface of the target is parallel to the surface of the substrate, so that the optimal utilization rate of the target, the uniformity of the deposited film and the like are achieved. However, such a structure results in a low coverage of the deposited film with respect to the three-dimensional structure (conformal), i.e. the deposition process results in a thickness of the side of the three-dimensional structure (δ c) which is much less than the thickness of the surface of the three-dimensional structure (δ T), typically δ c < < 30% δ T.

SUMMERY OF THE UTILITY MODEL

To the not enough of the above-mentioned prior art, the utility model provides a gas spraying unit that has can be used for the blowout like the process gas of oxygen to promote the chemical reaction between the granule of sputter deposition in-process gas and target sputtering department, the orifice can be along tracheal length direction evenly distributed, makes chemical reaction can be basically even going on the surface of wafer.

Meanwhile, the sputtering target adopts remote ion assistance, namely an additional ion source is adopted, so that plasma is generated in the sputtering process, and the plasma acts on the surface of the sputtering target through electromagnetic field guidance, so that the plasma concentration on the surface of the target is strongly improved, and the sputtering rate of the system is further improved.

In order to improve the coverage rate of the film deposited on the three-dimensional structure, the target material and the surface of the substrate of the system are designed to have adjustable angles, and the substrate can also rotate in the sputtering process, so that the coverage rate of the sputtered film is greatly improved, and the delta c is between 50 percent and delta T.

In order to achieve the above purpose, the utility model provides a following technical scheme: the utility model provides a PVD system of ion assistance, slope sputtering, includes the cavity, is provided with plasma source, target holder and base plate objective table in the cavity, be provided with the gas around the front of base plate objective table and spray the unit.

The gas spraying unit further comprises a plurality of spray holes, the plurality of spray holes are uniformly distributed on the inner side of the gas spraying ring along the circumference, and a gas passage communicated with the spray holes is formed in the gas spraying ring.

Further the gas spraying unit is located between the substrate objective table and the target support and comprises a gas pipe, the gas pipe comprises a gas inlet and a plurality of spray holes, and the spray holes incline towards the direction of the substrate objective table.

An openable baffle is arranged in front of the substrate carrying table.

Further, a sealing unit is arranged on the front surface of the substrate carrying table, the sealing unit is arranged along the outline shape of the substrate carrying table, the substrate is arranged on the sealing unit, a cavity is formed between the substrate and the substrate carrying table, and a gas channel communicated to the cavity is formed in the substrate carrying table.

Furthermore, a cooling channel is arranged in the substrate stage, and a cooling medium is introduced into the cooling channel.

The target support is further positioned below the plasma source, the front surface of the target support is obliquely arranged at an angle with the central axis of the plasma source, and the front surface of the substrate object stage faces the front surface of the target support and is far away from the central axis of the plasma source.

Further a top magnet and/or a bottom magnet is disposed within the chamber, the top magnet located at the plasma source and the bottom magnet located at the substrate stage.

Further said top magnet is arranged at an angle of 0-90 ° to the axis of the plasma source.

Further the bottom magnet is disposed at an angle of 0-90 ° to the centerline of the substrate stage.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the uniform spraying holes of the reaction gas around the substrate are easy to control the reaction sputtering process, and the uniformity of the film on the surface of the substrate is improved;

2. the remote ion source assists sputtering, and the magnet guides the plasma to improve the ion concentration;

3. oblique sputtering is carried out, so that the coating rate of the sputtered film is improved;

4. the top magnet and the bottom magnet are used for guiding the plasma distribution, so that the plasma concentration on the surface of the target is improved, and the sputtering rate is improved.

Drawings

FIG. 1 is a schematic diagram of a first embodiment of an ion-assisted, tilted sputtering PVD system of the present invention;

FIG. 2 is a schematic structural diagram of a second embodiment of an ion-assisted, tilted sputtering PVD system of the present invention;

fig. 3 is a schematic perspective view of a first embodiment of the gas spraying unit of the present invention;

FIG. 4 is a cross-sectional view of a first embodiment of the middle gas spraying unit of the present invention

FIG. 5 is a schematic structural view of a second embodiment of the gas spraying unit of the present invention;

FIG. 6 is a schematic view of the substrate stage with baffles according to the present invention;

fig. 7 is a cross-sectional view of the substrate stage according to the present invention.

Reference numerals: 1. a chamber; 2. a plasma source; 21. sputtering a shielding case; 3. a target holder; 4. a substrate stage; 41. a plate; 42. a baffle plate; 43. a shaft; 45. an air injection ring; 51. a top magnet; 52. a bottom magnet; 6. a substrate; 7. an air tube; 71. spraying a hole; 72. a gas inlet; 73. an airway; 81. a seal ring; 82. a gas channel; 83. a cavity; 84. a vacuum pump; 85. a capacitance manometer; 86. a controller; 87. a valve; 88. a mass flow controller; 89. a cooling channel.

Detailed Description

Embodiments of the ion assisted, tilted sputtering PVD system of the present invention are further described with reference to fig. 1-7.

In the description of the present invention, it should be noted that, for the orientation words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and the positional relationship are indicated based on the orientation or the positional relationship shown in the drawings, and the description is only for convenience of describing the present invention and simplifying the description, but not for indicating or implying that the device or the element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present invention.

Furthermore, if the terms "first" and "second" are used for descriptive purposes only, they are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. Thus, the definition of "a first" or "a second" feature may explicitly or implicitly include one or more of the features, and "a plurality" or "a plurality" in the description of the invention means two or more unless a specific definition is explicitly provided.

The PVD system comprises a chamber 1, wherein a plasma source 2, a target support 3 and a substrate stage 4 are arranged in the chamber 1, and a gas spraying unit is arranged around the front face of the substrate stage 4.

The front surface of the substrate stage 4 refers to a surface for placing a substrate 6 such as a wafer.

As shown in fig. 3 and 4, it is the structural schematic diagram of the first embodiment of the middle gas spraying unit of the present invention, the gas spraying unit includes an air spraying ring 45, the middle of the substrate stage 4 corresponding to the air spraying ring 45 is used for placing the substrate 6, the gas spraying unit further includes a plurality of spray holes 71, the plurality of spray holes 71 are uniformly distributed along the circumference at the inner side of the air spraying ring 45, the air spraying ring 45 is provided with a gas channel 73 communicated with the spray holes 71, one end of the gas channel 73 is a gas inlet 72, and the gas inlet 72 is connected with a gas source.

In this embodiment, in order to make the gas flow ejected from all the nozzle holes 71 uniform, it is preferable that the path distances of the gas passages 73 from the inlets of the gas passages 73 to all the nozzle holes 71 are the same, specifically, as shown in fig. 4, a multi-stage channel form may be adopted, each channel is divided into two branches as a next-stage channel, the path distances of the two branches of the same stage are the same, and the last-stage channel forms the nozzle hole 71.

As shown in fig. 5, it is the structural schematic diagram of the second embodiment of the middle gas spraying unit of the present invention, the gas spraying unit is located between the substrate stage 4 and the target holder 3, the gas spraying unit includes a gas pipe 7, the gas pipe 7 includes a gas inlet 72 and a plurality of nozzle holes 71, and the nozzle holes 71 incline towards the substrate stage 4.

In this embodiment, e.g. a substrate 6 is placed on the substrate stage 4, a target is arranged on the target holder 3, a gas shower unit is arranged between the substrate 6 and the target, and a gas tube 7 of the gas shower unit may be made of a corrosion resistant material, e.g. stainless steel, for durability and consistency. The gas inlet 72 is attached to a plate 41 fixed to the substrate stage 4, which plate can be used to support and stabilize the gas pipe 7 so that the distance D3 between the gas pipe 7 and the substrate stage 4 is kept constant.

In the embodiment, the gas pipe 7 has a plurality of nozzles 71, as shown in fig. 5, which can be used to eject a process gas such as oxygen to promote a chemical reaction between the process gas and particles sputtered from the target during a sputter deposition process, and the nozzles 71 can be uniformly distributed along the length of the gas pipe 7, so that the chemical reaction can be performed substantially uniformly on the surface of the wafer.

In the present embodiment, the gas pipe 7 is located in front of the substrate stage 4 to substantially conform to the contour of the substrate stage 4, that is, to the shape of the substrate 6, and if the substrate 6 represents a circular substrate 6, the gas pipe 7 has a circular ring shape, so that the uniformity of the thin film formed on the substrate 6 is greatly improved.

The utility model discloses it is preferred the place ahead of base plate objective table 4 is provided with baffle 42 that can open, as shown in fig. 6, baffle 42 rotates with board 41 on the base plate objective table 4 through axle 43 and is connected to the baffle 42 in this embodiment to preferably through motor drive, baffle 42 can be rotatory around axle 43, so that it covers or does not cover substrate 6 on the base plate objective table 4, of course baffle 42 also can cover or does not cover substrate 6 through the mode of translation.

As shown in fig. 7, in the embodiment, a sealing unit is disposed on the front surface of the substrate stage 4, the sealing unit is disposed along the contour shape of the substrate stage 4, the substrate 6 is disposed on the sealing unit, the sealing unit may be, for example, a sealing ring 81, a cavity 83 is formed between the substrate 6 and the substrate stage 4, a gas passage 82 communicated to the cavity 83 is opened on the substrate stage 4, the substrate 6 can be attached to the sealing unit by connecting the gas passage 82 to a vacuum pump 84, and in this case, the manufacturing of the substrate stage 4 can be simplified.

A capacitance manometer 85 for measuring a flow rate of gas drawn from the cavity 83 may be provided between the gas passage 82 and the vacuum pump 84, and a controller 86 for cooperating with the capacitance manometer 85 may be further included, the controller 86 controlling the flow rate of the drawn gas to thereby control the pressure of the gas in the cavity 83.

Preferably, a branch between the gas channel 82 and the capacitance manometer 85 is provided, which is provided with a valve 87 and a mass flow controller 8886, wherein the gas can be introduced into the cavity 83 by opening the valve 87, and the gas in the cavity 83 is controlled to maintain a constant pressure during the deposition process by the valve 87, the mass flow controller 8886, the capacitance manometer 85, the controller 86 and the vacuum pump 84.

During deposition, the gas within cavity 83 may act as a thermal conductor between substrate 6 and substrate stage 4, such that substrate 6 and substrate stage 4 are thermally conductive.

In the preferred embodiment, a cooling channel 89 is disposed in the substrate stage 4, a cooling medium is introduced into the cooling channel 89, and as shown in fig. 7, water or a water-alcohol mixture is introduced into the cooling channel 89 as the cooling medium, and the cooling medium is made to flow through the substrate stage 4 to accelerate heat dissipation.

As shown in fig. 1, the target holder 3 is preferably located below the plasma source 2 in this embodiment, and the front surface of the target holder 3 is inclined at an angle to the central axis of the plasma source 2, and the front surface of the substrate stage 4 faces the front surface of the target holder 3 and is away from the central axis of the plasma source 2.

Wherein the preferred substrate stage 4 may employ a rotation mechanism to enable in-situ rotation of the substrate 6 about an axis.

Of course, the substrate stage 4 as a whole can be rotated relative to the target holder 3 to adjust the angle between it and the target holder 3.

The central axis of the plasma source 2 is the plasma path in this embodiment and the substrate stage 4 keeps the substrate away from the plasma path but directs the substrate towards the sputtering surface of the target on the target holder 3 to maximise deposition of sputtered material on the substrate.

The target holder 3 in this embodiment preferably can rotate the target material by using a rotating mechanism, but the inclination angle of the target holder 3 is preferably adjustable, but these are not essential.

In fig. 1, a plasma source 2 having a plasma generation region is shown that employs a radio frequency RF power supply and coils to generate plasma, and the plasma from the plasma source 2 interacts with a target to increase the target surface plasma concentration to assist in sputtering material from the surface of the target onto a substrate 6.

The plasma source 2 in this embodiment is generally cylindrical and is generally symmetrical with respect to its central axis, the surface of the target is inclined at an acute angle with respect to the central axis of the plasma source 2 for efficient sputtering, and the inclination angle of the sputtering surface of the target with respect to the central axis of the plasma source 2 is such that most of the sputtered material from the sputtering surface of the target is directed away from the plasma source 2, so that when the power is applied to the target, the plasma in the chamber, including the plasma generated from the plasma source 2 and collected and confined on the surface of the target, hits the surface of the target to sputter material, due to the inclination angle of the sputtering surface of the target, a large amount of sputtered material is directed away from the plasma source 2, and therefore, the amount of sputtered material from the reverse sputtering plasma source 2 can be minimized, and the substrate 6 is oriented toward the target sputtering surface to maximize deposition of sputtered material sputtered from the target sputtering surface.

In the present embodiment, it is preferable that a sputtering shield 21 is provided in the chamber 1 at an opening corresponding to the plasma source 2 to reversely sputter the sputtering material into the plasma source 2 by a minimized amount.

As shown in fig. 1, two magnets, a top magnet 51 and a bottom magnet 52, are also shown in this embodiment, which may be electromagnetic coils or ring magnets. The top and bottom magnets 51, 52 may generate magnetic fields with asymmetric strengths, thereby forming magnetic field lines that may be manipulated to control the concentration of ions emitted by the plasma source 2 and reaching the target.

The preferred target in this embodiment is disk-shaped to maximize the efficiency of sputtering material toward the sputtering surface of the substrate 6 while minimizing unwanted sputtering from other surfaces of the target.

The target in this embodiment may also be a polygonal disk, and the sputtering surface of the target may be flat, concave, convex or non-flat, although the target may not be a disk but still have a sputtering surface.

In the present embodiment, the source gas may be introduced into the plasma generation region of the plasma source 2 to facilitate plasma generation, and since the source gas is directly injected into the plasma generation region in the present embodiment, a high pressure exists in the plasma generation region to support a high density plasma without requiring excessive energy of the RF coil, and the exhaust gas in the chamber 1 may be extracted through the port in the present embodiment.

As shown in fig. 2, the bottom surface of the top magnet 51 and the top surface of the bottom magnet 52 in the present embodiment are preferably arranged either parallel or at an angle with respect to the central axis of the plasma source 2 and the center line of the target holder 3, respectively, i.e., the top magnet 51 and the bottom magnet 52 may be asymmetric.

And the top and bottom magnets 51, 52 may be set to different amperages to produce different strength magnetic fields or different magnets' positions, sizes, windings, etc.

The top and bottom magnets 51, 52 may generate at least one magnetic field having a center line that passes through the sputtering surface of the target by adjusting the magnetic field strength and angle such that the center line passes through the surface of the target at a position lower than the center point of the target, i.e., the top and bottom magnets 51, 52 may be oriented such that relatively more magnetic field lines pass through the lower portion of the target, thereby increasing the plasma density at the lower portion of the sputtering surface of the target to compensate (the plasma source 2 is relatively further away from the lower portion of the target), making the plasma density substantially uniform over the sputtering surface of the target, and the consumption of the target substantially uniform over the sputtering surface, further allowing optimal utilization of the target, minimizing waste due to uneven or concentrated consumption of the sputtering surface of the target.

The top magnet 51 and/or the bottom magnet 52 may also be perpendicular to the central axis of the plasma source 2 and the center line of the target holder 3, respectively, in this embodiment.

The preferred top and bottom magnets 51, 52 are coupled with an adjustment mechanism for adjusting the tilt angle of the top and bottom magnets 51, 52 to optimize the utilization of the target or to optimize the deposition of sputtered material on the substrate 6.

Wherein the top magnet 51 and the bottom magnet 52 can be annular low-cost permanent magnets or electromagnets, so that the magnetic field intensity can be adjusted and controlled.

The rotating mechanism and the adjusting mechanism in the above embodiments may be powered by pneumatic power, electric power or magnetic power, and in the case of electric power, a stepping motor may be used.

Such as a stepper motor connected to the substrate stage 4 and a stepper motor connected to the target holder 3 for rotation of the substrate and target, respectively.

Such as a top magnet 51 and/or a bottom magnet coupled to change the tilt angle thereof using a stepper motor and gear engagement.

Of course, the substrate, target, top magnet 51 and bottom magnet 52 may also be stationary, as shown in fig. 1.

It is above only the utility model discloses a preferred embodiment, the utility model discloses a scope of protection does not only confine above-mentioned embodiment, the all belongs to the utility model discloses a technical scheme under the thinking all belongs to the utility model discloses a scope of protection. It should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. The utility model provides a PVD system of ion-assisted, slope sputtering, includes the cavity, is provided with plasma source, target holder and base plate objective table in the cavity, its characterized in that: and a gas spraying unit is arranged around the front surface of the substrate carrying table.

2. The ion assisted, tilted sputtering PVD system of claim 1, wherein: the gas spraying unit comprises a gas spraying ring, the middle of the substrate carrying table, corresponding to the gas spraying ring, is used for placing a substrate, the gas spraying unit further comprises a plurality of spray holes, the plurality of spray holes are uniformly distributed on the inner side of the gas spraying ring along the circumference, and a gas passage communicated with the spray holes is formed in the gas spraying ring.

3. The ion assisted, tilted sputtering PVD system of claim 1, wherein: the gas spraying unit is positioned between the substrate objective table and the target support and comprises a gas pipe, the gas pipe comprises a gas inlet and a plurality of spray holes, and the spray holes incline towards the direction of the substrate objective table.

4. The ion assisted, tilted sputtering PVD system of claim 3, wherein: an openable baffle is arranged in front of the substrate object stage.

5. The ion assisted, tilted sputtering PVD system of claim 4, wherein: the sealing unit is arranged on the front surface of the substrate carrying table, the sealing unit is arranged along the outline shape of the substrate carrying table, the substrate is arranged on the sealing unit, a cavity is formed between the substrate and the substrate carrying table, and a gas channel communicated to the cavity is formed in the substrate carrying table.

6. The ion assisted, tilted sputtering PVD system of claim 5, wherein: and a cooling channel is arranged in the substrate object stage, and a refrigerant is introduced into the cooling channel.

7. The ion assisted, tilted sputtering PVD system of claim 6, wherein: the target holder is positioned below the plasma source, the front surface of the target holder is obliquely arranged at an angle with the central axis of the plasma source, and the front surface of the substrate stage faces the front surface of the target holder and is far away from the central axis of the plasma source.

8. The ion assisted, tilted sputtering PVD system of claim 7, wherein: a top magnet and a bottom magnet are disposed within the chamber, the top magnet is located at the plasma source, and the bottom magnet is located at the substrate stage.

9. The ion assisted, tilted sputtering PVD system of claim 8, wherein: the top magnet is arranged at an angle of 0-90 degrees with the central axis of the plasma source.

10. The ion assisted, tilted sputtering PVD system of claim 8, wherein: the bottom magnet is arranged at an angle of 0-90 degrees with respect to the centerline of the substrate stage.

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