Physical vapor deposition equipment capable of reducing the coating on the back side of a wafer

Abstract

The present invention provides a physical vapor deposition device capable of reducing the coating on the back side of a wafer, comprising: a deposition chamber, a support base and a support ring located in the deposition chamber; the support ring is disposed above the circumferential edge of the support base in a surrounding manner, and the support ring includes a first part and a second part. The center of the first part has an opening exposing the central area of the support base, and a first annular protrusion for directly contacting the back side of the wafer during deposition to mount the wafer on the support base is provided on the annular surface of the first part; the second part is connected to the outside of the first part in a surrounding manner, and the upper surface of the second part is lower than that of the first part, so that the outermost peripheral area of the back side of the wafer is in a suspended state, and the periphery of the second part extends downward to the side surface of the support base. The present invention can effectively reduce the risk of debris while avoiding the coating on the back side of the wafer, and helps to reduce the risk of sticking and improve the process yield.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit manufacturing technology, and more particularly to integrated circuit manufacturing equipment, and especially to a physical vapor deposition equipment that can reduce the coating on the back side of a wafer. Background Art

[0002] Physical Vapor Deposition (PVD for short) is a technology that, under vacuum conditions, physically vaporizes gaseous atoms, molecules or partially ionizes ions from the surface of a solid and / or liquid material source, and deposits a thin film with a certain special function on the surface of a substrate through a low-pressure gas or plasma process. The PVD coating technology is widely used in the fields of semiconductors, optics, electronics, etc. For example, in semiconductor manufacturing, the PVD coating technology can be used to prepare thin films such as metal electrodes and insulating layers, which plays a key role in improving the performance and reliability of semiconductor devices. However, during the PVD coating process, when the particles sputtered from the target fly towards the wafer, due to factors such as particle scattering, reflection, and the distribution of electric and magnetic fields, some particles will reach the edge and back of the wafer and deposit thereon, resulting in unwanted coatings on the edge and back of the wafer. The coatings on the edge and back of the wafer will have many adverse effects on the product performance. For example, in a semiconductor device, the coating on the back of the wafer may change its electrical properties and affect the normal operation of the device; the uneven coating on the edge may cause stress concentration, reducing the mechanical strength and reliability of the wafer, and even affecting subsequent packaging processes, etc. Therefore, how to effectively prevent the coating on the edge and back of the wafer is an urgent problem to be solved in the PVD coating process.

[0003] In the prior art, in order to prevent the coating on the back of the wafer, a commonly used method is to use a retainer ring to press the wafer to prevent back plating; another is to completely attach the back surface of the wafer, especially the edge surface of the wafer, to the support surface of the support platform to form a back shield for the wafer. However, the former method is prone to cause fragmentation, and the latter method is prone to cause adhesion between the wafer and the support platform, which will also cause damage to the wafer.

[0004] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art just because these solutions are described in the background art part of the present invention. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the object of the present invention is to provide a physical vapor deposition device, which is used to solve the problems in the prior art that when using a pressing ring to press the wafer to prevent back plating, it is easy to cause fragments; when using the method of completely attaching the edge surface of the wafer to the supporting surface of the supporting platform to form a back shielding for the wafer to prevent back plating of the wafer, it is easy to cause adhesion between the wafer and the supporting platform, which will also cause damage to the wafer and other problems.

[0006] To achieve the above object and other related objects, a physical vapor deposition device capable of reducing back plating of a wafer according to the present invention includes: a deposition chamber, a supporting base and a supporting ring located in the deposition chamber; the supporting ring is arranged above the circumferential edge of the supporting base, and the supporting ring includes a first part and a second part. The center of the first part has an opening exposing the central area of the supporting base, and a first annular protrusion for directly contacting the back surface of the wafer during deposition to mount the wafer on the supporting base is arranged on the annular surface of the first part; the second part is connected to the outside of the first part, and the upper surface of the second part is lower than that of the first part, so that the outermost peripheral area of the back surface of the wafer is in a suspended state, and the outer periphery of the second part extends downward to the side surface of the supporting base.

[0007] Optionally, the height difference between the top surface of the first annular protrusion and the top surface of the supporting base is 0.2 mm - 2 mm, and the radial dimension of the top surface of the first annular protrusion is 0.5 mm - 1 mm.

[0008] Optionally, the outer periphery of the second part extends obliquely downward to form an inclined slope surface, and the formed inclined slope surface is coplanar with the side surface of the wafer.

[0009] Optionally, the upper surface of the second part has a second annular protrusion, there is a spacing between the second annular protrusion and the first annular protrusion, and the height of the second annular protrusion is lower than that of the first annular protrusion.

[0010] Optionally, a conductive material layer is arranged on the surface of the second annular protrusion, and the negative bias voltage applied to the conductive material layer is greater than the negative bias voltage applied to the supporting base.

[0011] Optionally, an annular groove is arranged between the first annular protrusion and the second annular protrusion, and air holes communicating with a vacuum device are formed on the bottom surface of the annular groove to form a negative pressure environment capable of adsorbing target particles in the annular groove.

[0012] Optionally, the physical vapor deposition device further includes an annular cleaning gas pipeline located above the supporting ring, and a plurality of air holes with openings facing obliquely downward are evenly spaced on the cleaning gas pipeline for spraying inert gas toward the side surface of the wafer in an obliquely outward manner.

[0013] In an alternative embodiment, the support ring is made of ceramic, its surface is treated by sandblasting, and the first part and the second part are integrally formed.

[0014] In another alternative embodiment, the first part and the second part are detachably connected.

[0015] Optionally, the central region of the support base is higher than the peripheral region circumferentially surrounding the central region. The physical vapor deposition apparatus further includes a deposition ring, which is mounted on the surface of the peripheral region of the support base and extends downward and outward. The support ring is placed on the deposition ring.

[0016] As described above, the physical vapor deposition apparatus provided by the present invention, which can reduce the coating on the back side of the wafer, has the following beneficial effects: Through the optimized structural design, the present invention provides a support ring including a first part and a second part in the deposition chamber. A first annular protrusion is provided on the annular surface of the first part for directly contacting the back side of the wafer during deposition to place the wafer on the support base; the second part is connected to the outside of the first part, and the upper surface of the second part is lower than that of the first part, so that the outermost peripheral region of the back side of the wafer is in a suspended state, and the outer periphery of the second part extends downward to the side surface of the support base. This can effectively reduce the risk of debris while effectively reducing the coating on the back side of the wafer, and can avoid the adhesion between the wafer and the support base and the process kit, which helps to improve the process yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It shows a schematic cross-sectional structure diagram of the physical vapor deposition apparatus provided by the present invention for reducing the coating on the back side of the wafer in an example.

[0018] Figure 2 Shown as Figure 1 a partial enlarged schematic diagram in

[0019] Figure 3 Shown as Figure 2 an enlarged schematic diagram of area A in

[0020] Figure 4 It shows a schematic diagram of the working principle of the present invention for arranging a cleaning gas pipeline above the wafer.

[0021] Figure 5 It shows a partial cross-sectional structure diagram of the physical vapor deposition apparatus provided by the present invention for reducing the coating on the back side of the wafer in another example.

[0022] Figure 6 Shown as Figure 5 an enlarged schematic diagram of area B in an example in

[0023] Figure 7 Shown as Figure 5The enlarged schematic diagram of area B in [another example]. Detailed implementation mode

[0024] The following uses specific specific examples to illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. When detailing the embodiments of the present invention, for the convenience of description, the cross-sectional views showing the device structure will be enlarged locally not in accordance with the general ratio, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention here. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0025] For the convenience of description, spatial relationship terms such as "under", "below", "lower than", "beneath", "above", "on" may be used herein to describe the relationship between one element or feature shown in the drawings and other elements or features. It will be understood that these spatial relationship terms are intended to encompass other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers.

[0026] In the context of the present invention, the structure in which the first feature is "above" the second feature described may include an embodiment in which the first and second features are formed in direct contact, and may also include an embodiment in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0027] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex. To make the diagrams as concise as possible, not all structures are labeled in each drawing.

[0028] In existing sputtering coating equipment, in order to reduce the back coating of the wafer, a common method is to place the entire back of the wafer on the support platform so that sputtering particles cannot enter the back of the wafer. However, this method is likely to affect the coating quality due to adhesion between the coating at the edge of the wafer and the support platform. Another method is to press a retaining ring on the front edge of the wafer, which is likely to cause fragmentation. Or if both methods are used simultaneously, the above risks exist simultaneously. Therefore, through long-term and extensive research, the inventor of this case has proposed an improvement solution.

[0029] Specifically, as Figures 1 to 3 shown, the present invention provides a physical vapor deposition apparatus capable of reducing the coating on the back surface of a wafer 14, which includes a deposition chamber 11, a support base and a support ring 13 located in the deposition chamber 11.

[0030] The support ring 13 is disposed around the circumferential edge of the support base above it, and includes a first part 13a and a second part 13b. The center of the first part 13a has an opening exposing the central area of the support base. Since the wafer 14 is coaxially placed with the support base, the central area of the support base corresponds to the central area of the wafer 14 up and down. A first annular protrusion 131 is provided on the annular surface of the first part 13a for directly contacting the back surface of the wafer 14 during deposition to mount the wafer 14 on the support base; the second part 13b is connected to the outside of the first part 13a, and the upper surface of the second part 13b is lower than that of the first part 13a. Therefore, when the wafer 14 is placed on the support ring 13, the second part 13b does not directly contact the wafer 14, which makes the bottom of the outermost area of the back surface of the wafer 14 not in contact with other solid structures including the support ring 13 and in a suspended state, or in other words, there is a gap between the edge part of the back surface of the wafer 14 and the support ring 13. In addition, the outer periphery of the second part 13b of the support ring 13 extends downward to the side surface of the support base.

[0031] The deposition chamber 11 can be a metal chamber such as an aluminum alloy or stainless steel chamber, and generally can be in a hollow cylindrical structure. The inner wall of the chamber can be coated with an anti-corrosion coating such as ceramics. An exhaust port is provided in the middle and lower part of the deposition chamber 11. During the film deposition process, the deposition chamber 11 can be grounded. A sputtering assembly is provided in the upper part of the deposition chamber 11, and the sputtering assembly at least includes a target source 17 and a sputtering power supply (not shown). The target source 17 includes, for example, metal target materials such as copper targets and aluminum targets, or other non-metal target materials. According to different needs, the sputtering power supply can be a DC power supply or an RF power supply. For example, in some examples, the physical vapor deposition device is RF sputtering, and then an RF power supply is used. In some better examples, the physical vapor deposition device is a magnetron sputtering device, and the sputtering assembly further includes a magnet located on the back of the target material. The magnet can be a permanent magnet and / or an electromagnet. A sputtering gas inlet pipeline is provided on the deposition chamber 11, and the sputtering gas inlet pipeline is, for example, provided at a position near the target material in the upper part of the deposition chamber 11 for inputting an inert gas such as argon into the deposition chamber 11. Argon is ionized into ions under the action of an external electric field and bombards the material target source 17 in a high-voltage environment, and the atoms or molecules of the target material are ejected and fly towards the surface of the wafer 14, thereby depositing a film. If it is used for depositing an insulating film, in addition to the inert gas for sputtering, reaction gases such as oxygen and nitrogen for deposition reaction need to be input into the deposition chamber 11. The reaction gas and the sputtering gas can be input into the deposition chamber 11 through the same inlet pipeline or through different inlet pipelines. To improve the film deposition performance, the sputtering assembly can include a power source for rotating and / or lifting the target material and / or the magnet, and / or a cooling device, and specific limitations are not made.

[0032] In some examples, a baffle for preventing particles from splashing onto the inner wall of the deposition chamber 11 may be provided in the deposition chamber 11. The baffle may extend downward from the periphery of the target along the inner wall of the chamber to the outer periphery of the support base. The baffle may be made of the same material as the deposition chamber 11, such as aluminum alloy or stainless steel, and its surface may be coated with a corrosion-resistant coating. The baffle may be of an integral or split structure. For example, in the examples of the present invention, the baffle includes an upper baffle 15 and a lower baffle 16. The upper part of the upper baffle 15 is located outside the target and extends downward above the periphery of the wafer 14; the upper part of the lower baffle 16 is connected to the inner wall of the deposition chamber 11 and extends downward to the outer periphery of the support base. The lower part of the upper baffle 15 and the upper part of the lower baffle 16 are partially juxtaposed to seamlessly shield the inner wall of the deposition chamber 11. In some examples, the physical vapor deposition apparatus further includes a shielding ring 18 disposed above the support base. For example, in this embodiment, a U-shaped groove is formed in the part of the lower baffle 16 close to the support base, and the shielding ring 18 is buckled on the lower baffle 16. The through hole in the center of the shielding ring 18 is smaller than the size of the wafer 14, and its annular surface is located directly above the non-coated area at the edge of the wafer 14, for preventing the non-coated area at the edge of the wafer 14 from being coated. And in this embodiment, there is a spacing between the shielding ring 18 and the wafer 14, that is, it does not press on the edge surface of the wafer 14. That is, the front side of the wafer 14 in this embodiment does not directly contact any process kit. In a further example, a cover ring 19 is also provided between the shielding ring 18 and the target. The cover ring 19 is, for example, conical, and the opening at its bottom is slightly larger than the opening size of the shielding ring 18. The cover ring 19 presses on the shielding ring 18, and its bottom end also falls into the U-shaped groove of the lower baffle 16. The provision of the cover ring 19 can play a role in converging and guiding the sputtered particles, guiding the sputtered particles to reach the coating area on the front side of the wafer 14. The shielding ring 18 and the cover ring 19 may be made of ceramic materials such as alumina, aluminum nitride, zirconia, or composite materials with a ceramic layer plated on a metal substrate surface.

[0033] The support base has a support platform 121 in the shape of a disc for placing the wafer 14, and may further include a support shaft 122 connected to the bottom of the support platform 121 and extending downward to the outside of the deposition chamber 11. According to different processes, the support platform 121 may be made of metal materials such as aluminum, or ceramic materials such as aluminum nitride. The support shaft 122 may be electrically connected to a drive motor (not shown) to drive the support platform 121 to rotate and / or lift when needed. In some examples, positioning holes 123 and / or thimble lifting holes 124 may be provided in the support platform 121. The positioning hole 123 may be provided at the center of the support platform 121, which may be used as a positioning mark when the wafer 14 enters and exits the chamber, ensuring that the position of the wafer 14 does not shift when entering and exiting the chamber.

[0034] A heater may be provided inside the support platform 121. The heater is, for example, a heating resistance wire wound around the support base. In some examples, a cooling layer may also be provided inside the support base. The cooling layer includes, for example, a spirally wound water-cooling and / or air-cooling pipeline to cool the wafer 14 located above the support base when needed. In addition, an electrode connected to a bias power supply may be provided in the support platform 121. Various source lines, including power lines and cooling pipelines, can extend from the outside to the support platform 121 via the support shaft 122.

[0035] In the prior art, the upper surface of the support base is usually a flat surface, and the entire back surface of the wafer is directly placed against the support base. In the example provided by the present invention, an annular support ring 13 is provided above the edge of the support base. The support ring 13 sequentially includes a first part 13a and a second part 13b from inside to outside in the radial direction. The opening inside the first part 13a exposes the central area of the support base. A first annular protrusion 131 is provided on the annular surface of the first part 13a. The top surface of the protrusion is higher than the horizontal plane of the support base, the back surface of the wafer 14, and usually the peripheral area of the back surface of the wafer 14 is directly placed against the first annular protrusion 131, so that the wafer 14 is lifted by the support ring 13 and erected on the support base. That is, the wafer 14 does not directly contact the support base, and the entire front surface of the wafer 14 is not provided with a physical barrier and is completely exposed to the deposition atmosphere (for example, a pressing ring is not placed on the front surface of the wafer 14, or although a pressing ring is provided above the front edge of the wafer 14, it does not directly contact the surface of the wafer 14). In some examples, an electrostatic adsorption or vacuum adsorption device may be provided on the support base to provide an adsorption force to the back surface of the wafer 14, thereby fixing the wafer 14 firmly on the support ring 13. In other examples, when ensuring that the air pressure on the front surface of the wafer 14 is not less than the air pressure on the back surface (the pressure on the front surface of the wafer 14 is not less than the pressure on the back surface), the wafer 14 can also be directly placed on the support ring 13 in a non-adsorbed manner. The height difference between the top surface of the first annular protrusion 131 and the top surface of the support base (this height difference is also the longitudinal distance between the back surface of the wafer 14 and the support base) should not be too large or too small. If the distance is too large, the wafer 14 is prone to shift; if the distance is too small, a good technical effect cannot be achieved. In the preferred example provided in this embodiment, the height difference between the two is 0.2 mm - 2 mm, that is, the first annular protrusion 131 is 0.2 mm - 2 mm higher than the top surface of the support base, preferably 0.5 mm - 1 mm. The top surface of the first annular protrusion 131 can be a spherical surface or a rectangular plane, and the radial dimension of its top surface is preferably 0.5 mm - 1 mm. Since the wafer 14 directly lands on the first annular protrusion 131 of the support ring 13, the first annular protrusion 131 abuts against the back edge of the wafer 14, forming a wall, so that sputtering particles cannot enter the central area of the back surface of the wafer 14, which can greatly improve the back surface coating phenomenon of the wafer 14.

[0036] The support ring 13 can be directly placed on the horizontal surface of the support platform 121. The advantage is that the device structure is simple, but the disadvantage is that the support ring 13 may easily shift. In a preferred example, the central region of the support platform 121 is higher than the peripheral region circumferentially surrounding the central region, that is, the support platform 121 has a structure with a higher middle and lower edges, thereby forming a stepped surface at the edge of the support platform 121. In some examples, the support ring 13 can be directly placed on the surface of the peripheral region. For example, an annular groove is provided in the peripheral region, and an annular protrusion adapted to the annular groove is provided on the bottom surface of the support ring 13, so that the support ring 13 is embedded on the support platform 121 to achieve fixation between the two. In some other examples, it can also be as Figure 1 shown. The device further includes a deposition ring 20. The deposition ring 20 is erected on the surface of the peripheral region of the support base and extends downward and outward. The support ring 13 is placed on the deposition ring 20. The upper part of the deposition ring 20 is placed on the step at the edge of the support platform 121, its side extends downward along the side of the support platform 121, and a U-shaped space is formed at its end, which is not only convenient for connection with other kits, but also helps to block sputtering particles. The deposition ring 20 is preferably made of ceramic material. In a preferred example, there is a gap between the support ring 13 and the support base in the lateral direction, that is, the part of the support ring 13 surrounding the support base circumferentially does not contact the support base, or in other words, there is a distance between their sides. This distance is preferably between 0.5 mm and 1 mm. Setting the gap helps to reduce the friction between the two. In some examples, the adsorption force on the wafer 14 in this region can be adjusted by adjusting the pressure in the gap. For example, in some examples, the gap can be connected to a negative pressure device to provide negative pressure to the wafer 14, so that the wafer 14 is fixed on the support ring 13. In this case, there is no need to set up a vacuum adsorption pipeline on the support platform 121, which can not only make the applicable range of the available support base larger, but also prevent problems such as wire winding during the rotation of the support platform 121 when a vacuum adsorption pipeline is set on the support base (the gap is fixed, so if negative pressure is provided through the gap, the position of the negative pressure pipeline is fixed). The side of the deposition ring 20 and the side of the support base are also preferably in a non-abutting state, for example, there is also a gap of 0.5 mm - 1 mm, which helps to reduce the friction between the deposition ring 20 and the support platform 121.

[0037] There is no strict demarcation line between the second part 13b and the first part 13a of the support ring 13. In some examples, the first part 13a and the second part 13b are integrally processed. Then, the support ring 13 is preferably made of ceramic materials such as alumina, aluminum nitride, and zirconia. The surface can be treated by sandblasting or thermal spraying to increase the adsorption force of its surface to sputtering particles. In some other examples, the first part 13a and the second part 13b can also be detachably connected, and the two can be made of different materials. For example, in some examples, the first part 13a and the second part 13b are connected by means of mutual embedding. The advantage of using a split connection is that different sizes of the second part 13b can be selected according to different wafer 14 sizes, and when one part is damaged, it can be replaced in time, extending the service life of the spare parts.

[0038] In a preferred example, the outer periphery of the second part 13b extends obliquely downward to form an inclined slope surface 133, which can effectively avoid the diffraction of sputtering particles and further prevent the back surface of the wafer 14 from being coated with a film layer. When the side surface of the wafer 14 is an inclined surface, the formed inclined slope surface 133 is coplanar with the side surface of the wafer 14, thereby forming a diversion surface, which can more smoothly guide the sputtering particles diffused to the outer periphery of the edge of the wafer 14 to the inclined slope surface 133 on the outer periphery of the support ring 13.

[0039] In some examples, as Figure 4 shown, an annular cleaning gas pipeline 21 is provided above the support ring 13. The cleaning gas pipeline 21 is specifically located between the support ring 13 and the sputtering device. More specifically, for example, it is located below the aforementioned shielding ring 18. In some examples, the shielding ring 18 and the cleaning gas pipeline can be combined into one, or the shielding ring 18 also serves as the cleaning gas pipeline at the same time. For example, a plurality of air holes with openings facing obliquely downward are evenly spaced in the shielding ring 18, and an inert cleaning gas (such as argon or nitrogen) is sprayed obliquely to the non-coated area at the edge of the wafer 14 and the side surface of the wafer 14 through these air holes. Thus, an air curtain is formed in the edge area of the wafer 14, and the inert gas can perform edge purging on the wafer 14 to prevent sputtering particles from depositing on the edge and back surface of the wafer 14. In addition, the cleaning gas can also provide pressure to the front edge of the wafer 14, which helps to fix the wafer 14. When the inclined slope surface 133 of the second part 13b is coplanar with the side surface of the wafer 14, the sprayed cleaning gas can be discharged smoothly along the inclined slope surface 133 of the support ring 13 in the direction indicated by the arrow in Figure 4 and further purge the edge of the support base, which helps to prevent the surface of the support base and the support ring 13 from being coated with a film, improve its cleanliness, extend the service life, and reduce the use cost of the equipment.

[0040] In some other examples, air holes (not shown) connected to the inert gas device can be provided on the side surface of the first annular protrusion 131 for spraying inert gas toward the periphery of the back surface of the wafer 14 during the deposition process to prevent sputtering particles from entering the back surface area of the wafer 14, and can also serve the purpose of preventing the back surface of the wafer 14 from being coated. The sprayed gas should not affect the stability of the wafer 14. For example, the flow rate of the sprayed gas is within 50 sccm. In some examples, the scheme of providing air holes on the side surface of the first annular protrusion 131 and providing an embedded cleaning gas pipeline can be adopted simultaneously. In some examples, the edge temperature of the wafer 14 can also be adjusted by adjusting the temperature of the sprayed inert gas. For example, during the coating process, the temperature of the inert gas can be appropriately increased (e.g., higher than the process temperature) to reduce the temperature difference between the edge area and the central area of the wafer 14 and improve the coating uniformity. After the coating is completed, the temperature of the inert gas can be lower to accelerate the cooling of the edge area of the wafer 14 (including the back edge and the side surface of the wafer 14), which helps to improve the stress distribution at the edge of the wafer 14 and enhance the coating quality.

[0041] In some examples, the second part 13b can also be provided with a vertical portion 134 connected to the bottom of the inclined surface. The vertical portion 134 extends vertically downward into the groove of the deposition ring 20 to better fix the support ring 13 to the deposition ring 20.

[0042] In some other examples, referring to Figure 5 and Figure 6As shown, the upper surface of the second part 13b has a second annular protrusion 132. There is a spacing between the second annular protrusion 132 and the first annular protrusion 131, and the height of the second annular protrusion 132 is lower than that of the first annular protrusion 131. Therefore, during the process of the support ring 13 supporting the wafer 14, the second annular protrusion 132 does not contact the wafer 14. The distance between the first annular protrusion 131 and the second annular protrusion 132 is, for example, 5 mm - 10 mm, and the height difference between the two can be controlled at about 1 mm. For example, in a specific example, the height of the first annular protrusion 131 is 2 mm, the height of the second annular protrusion 132 is 1 mm, and the two are separated by 10 mm (this separation distance refers to the lateral distance between the highest points of the two). In some examples, there may be more than one second annular protrusion 132. For example, a plurality of annular protrusions with gradually decreasing heights are arranged at intervals in the direction away from the first annular protrusion 131, and specific details are not limited. In the case where there is a second annular protrusion 132 with a height smaller than that of the first annular protrusion 131, the wafer 14 only contacts the first annular protrusion 131, which can reduce the risk of sticking; the sputtering particles can at most reach the intermediate area between the first annular protrusion 131 and the second annular protrusion 132 and cannot pass through the first annular protrusion 131. Moreover, due to the further interception of the second annular protrusion 132, the back coating of the wafer 14 can be more effectively reduced. The first annular protrusion 131 and the second annular protrusion 132 can both be spherical protrusions or other shapes, and the connection area between the two can be a horizontal or non-horizontal plane, for example, a wavy surface. Each corner of the first part 13a and the second part 13b is preferably chamfered to avoid local particle accumulation.

[0043] In the case where the sputtered particles are conductive particles, especially conductive metal particles, in some examples, a conductive particle capture device can be provided on the support ring 13, especially on the second part 13b of the support ring 13. For example, in some examples, the conductive particle capture device includes a conductive material layer provided on the surface of the second annular protrusion 132. For example, the conductive material layer is located on the entire surface of the annular protrusion or only on the outer peripheral surface of the second annular protrusion 132 facing away from the first annular protrusion 131, and the negative bias voltage applied to the conductive material layer is greater than the negative bias voltage applied to the support base. Therefore, when conductive metal particles enter the area on the back surface of the wafer 14 that is not blocked by the support ring 13, the conductive particles will be adsorbed and captured by the conductive material layer, effectively avoiding coating on the back surface of the wafer 14. Given that the height difference between the second annular protrusion 132 and the first annular protrusion 131 is usually not very large, in order to avoid the top surface of the second annular protrusion 132 increasing due to excessive accumulation of conductive particles and contacting the wafer 14, the thickness of the conductive material layer should not be too large, specifically determined according to its process and / or the height of the second annular protrusion 132. For example, it is preferably controlled within 0.5 mm. The material of the conductive material layer should be such that it does not cause coating contamination, for example, the same as the target material. In some examples, the conductive material layer can be formed on the circumferential surface of the second annular protrusion 132 facing away from the first annular protrusion 131 by an electroplating process. Or a conductive material layer is formed on the entire surface of the second annular protrusion 132. In some other examples, the conductive material layer can also be independently provided on the surface of a partial area of the second part 13b, such as a conductive strip provided on the corner surface of the second part 13b and / or the surface of the second annular protrusion 132. In the case where the first part 13a and the second part 13b are detachably connected, if the metal particles captured on the surface of the second part 13b accumulate, they can be replaced in a timely manner.

[0044] In some other examples, as Figure 7 shown, an annular groove 135 is provided between the first annular protrusion 131 and the second annular protrusion 132. Air holes communicating with the vacuum device are formed on the bottom surface of the annular groove 135 to form a negative pressure environment in the annular groove 135 that can adsorb target particles. Thus, when the target particles enter between the first annular protrusion 131 and the second annular protrusion 132, they will be sucked into the annular groove and then discharged through the air holes, which also helps to reduce coating on the back surface of the wafer 14. At the same time, the provided negative pressure environment helps to better fix the wafer 14 on the support ring 13. And this method is applicable to the capture of charged particles and uncharged particles, and can be applied not only to metal target sputtering but also to non-metal target sputtering.

[0045] In some examples, the above-mentioned conductive material layer and negative pressure adsorption can also be used simultaneously to jointly capture the target particles splashed onto the back region of the wafer 14. The wires connecting the conductive material layer and the pipelines required for negative pressure adsorption can be embedded in the grooves on the back of the second part and extended to be connected / communicated with the external structure. The conductive particles splashed onto the back region of the wafer 14 will first be captured by the conductive material layer of the second annular protrusion 132. If the uncaptured particles escape to the space between the first annular protrusion 131 and the second annular protrusion 132, they will be pumped away. Through the dual measures, the coating on the back of the wafer is effectively reduced.

[0046] In summary, a physical vapor deposition device for reducing the coating on the back of a wafer provided by the present invention, through an optimized structural design, sets a support ring including a first part and a second part. On the annular surface of the first part, there is a first annular protrusion for directly contacting the back of the wafer during deposition to mount the wafer on the support base; the second part is connected to the outside of the first part, and the upper surface of the second part is lower than that of the first part, so that the outermost peripheral region of the back of the wafer is in a suspended state, and the periphery of the second part extends downward to the side of the support base. It can effectively reduce the coating on the back of the wafer while effectively reducing the risk of debris, and can avoid the adhesion between the wafer and the support base and the process kit, which helps to improve the process yield. The present invention can be used for the deposition of metal thin films, as well as various thin films such as insulating films and non-metal conductive thin films. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0047] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A physical vapor deposition device capable of reducing the backside coating of a wafer, characterized in that: include: A deposition chamber, a support base and a support ring located in the deposition chamber; The support ring is arranged above the circumferential edge of the support base, and includes a first part and a second part. The center of the first part has an opening that exposes the central area of ​​the support base, and the annular surface of the first part is provided with a first annular protrusion that is used to directly contact the back side of the wafer during the deposition process to mount the wafer on the support base; The second part is connected to the outside of the first part, and the upper surface of the second part is lower than the first part, so that the outermost area of ​​the back side of the wafer is in a suspended state, and the periphery of the second part extends downward to the side of the supporting base; the upper surface of the second part has a second annular protrusion, there is a gap between the second annular protrusion and the first annular protrusion, and the height of the second annular protrusion is lower than the first annular protrusion.

2. The physical vapor deposition device according to claim 1, characterized in that: The height difference between the top surface of the first annular protrusion and the top surface of the support base is 0.2mm-2mm, and the radial dimension of the top surface of the first annular protrusion is 0.5mm-1mm.

3. The physical vapor deposition device according to claim 1, characterized in that: The support ring and the support base have a gap in the lateral direction.

4. The physical vapor deposition device according to claim 1, characterized in that: The periphery of the second portion extends downwardly in an inclined manner to form an inclined slope surface, and the formed inclined slope surface is coplanar with the side surface of the wafer.

5. The physical vapor deposition device according to claim 1, characterized in that: A conductive material layer is provided on the surface of the second annular protrusion, and the negative bias voltage applied to the conductive material layer is greater than the negative bias voltage applied to the support base.

6. The physical vapor deposition device according to claim 1, characterized in that: An annular groove is arranged between the first annular protrusion and the second annular protrusion, and an air hole connected to a vacuum device is formed on the bottom surface of the annular groove to form a negative pressure environment in the annular groove that can adsorb target particles.

7. The physical vapor deposition device according to claim 1, characterized in that: The physical vapor deposition equipment also includes an annular cleaning gas pipeline located above the support ring, and a plurality of gas holes opening obliquely downward are evenly spaced on the cleaning gas pipeline for spraying inert gas toward the side of the wafer in an oblique outward manner.

8. The physical vapor deposition device according to claim 1, characterized in that: The support ring is made of ceramic, the surface of which is sandblasted, and the first part and the second part are integrally formed; or the first part and the second part are detachably connected.

9. The physical vapor deposition device according to any one of claims 1 to 8, characterized in that: The central area of ​​the support base is higher than the peripheral area arranged around the central area. The physical vapor deposition equipment also includes a deposition ring, which is mounted on the surface of the peripheral area of ​​the support base and extends downward and outward. The support ring is mounted on the deposition ring.

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