WO2024027361A1

WO2024027361A1 - Film coating device and method capable of improving deep hole filling

Info

Publication number: WO2024027361A1
Application number: PCT/CN2023/102156
Authority: WO
Inventors: 周云; 宋维聪
Original assignee: 上海陛通半导体能源科技股份有限公司
Priority date: 2022-08-02
Filing date: 2023-06-25
Publication date: 2024-02-08
Also published as: CN115161594A; CN115161594B

Abstract

The present invention provides a film coating device and method capable of improving deep hole filling. The device comprises a cavity, a target material bearing disc, a magnetic control assembly, a base, and a corrector. The target material bearing disc is located at the top of the cavity and used for fixing a target material, and the target material is electrically connected to a first pulse power supply, so that the first pulse power supply provides positive and negative asymmetric bipolar pulses. The magnetic control assembly is located above the target material bearing disc, the base is located in the cavity, the corrector is located between the target material and the base in the cavity, and the corrector and the base are spaced and insulated from the cavity. The corrector is electrically connected to a positive electrode of an external power supply to supply positive bias. The corrector comprises a plurality of correction units arranged at intervals. Each correction unit is of a vertically-through through hole structure, and the corrector is used for correcting an inclination angle of the cation movement direction of the target material. According to the present invention, the filling uniformity of the deep hole structure of a large aspect ratio can be greatly improved, the deposition rate is improved, the production cost is reduced, and the economic benefit is improved.

Description

Coating equipment and methods that can improve deep hole filling

Technical field

The present invention relates to the field of semiconductor manufacturing technology, specifically to a semiconductor manufacturing equipment, and in particular to a coating equipment and method that can improve deep hole filling.

Background technique

The magnetron sputtering technology of the Physical Vapor Deposition (PVD) process is a widely used method to deposit metal film layers and other related material layers in the integrated circuit manufacturing process. It is used to fill deep holes, through silicon holes and deep groove structures. main technologies. In the process of filling through-silicon vias using traditional PVD technology, most metal ions are scattered and fall on the wafer at large angles. However, for through-silicon vias with a high aspect ratio, the scattered metal ions are scattered along the vertical direction. When entering the inside of the through hole from a direction with a large inclination angle, most of it will fall on the opening and upper side wall of the deep hole structure, resulting in poor film coverage at the bottom and lower side wall of the through hole. The existing commonly used PVD deep hole filling technology is to form a negative bias voltage on the base of the magnetron sputtering equipment to attract plasma. The higher the negative bias voltage, the more metal positive ions will be attracted to the deep hole. in the structure.

The application of magnetron sputtering technology in deep hole filling is mainly to deposit a barrier layer and a copper seed layer inside the through silicon hole. The role of the barrier layer is to prevent copper from diffusing into silicon or silicon dioxide, and the role of the copper seed layer is to prevent copper from diffusing into silicon or silicon dioxide. It is to make a conductive layer for the subsequent electroplating process, so the PVD process has a very important impact on the step coverage of deep hole filling. If the film coverage of the barrier layer is poor, it will affect the reliability of deep hole and through-hole devices; if the coverage of the seed layer is poor, copper electroplating will not proceed normally, and voids will appear in deep holes and through holes after electroplating. or gaps, seriously affecting device performance.

Traditional long throw PVD technology not only has a slow deposition rate when filling through-hole and deep-hole structures with a high aspect ratio, but also has problems with poor filling uniformity, especially in the edge areas of the wafer. The deep hole structure will have an asymmetric distribution when filling, that is, the film thickness deposited on the left and right side walls of the deep hole structure is inconsistent, and the deep hole filling uniformity is poor.

In order to improve the above problems, some magnetron sputtering equipment is equipped with collimation tubes. The collimation tubes rely on physical barriers on the side walls to filter ions. Large-angle particles cannot pass through the collimation tubes and eventually fall into the collimation tube. On the side wall of the tube, only some small-angle particles can successfully pass through the collimator tube and be deposited on the wafer. This kind of magnetron sputtering equipment with collimator tube can solve the problem of poor filling uniformity of deep hole structures with low aspect ratio (aspect ratio less than 5:1) to a certain extent, but it still exists for structures with large aspect ratio. The problem of poor step coverage, in addition to the slow deposition rate, low target utilization, etc., and the high processing and maintenance costs of the collimator tube lead to increased coating costs.

Contents of the invention

In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a coating equipment and method that can improve deep hole filling, so as to solve the problem of uniform filling in existing deep hole filling technology, such as traditional long-throw technology. Sex is not good, but with The magnetron sputtering equipment of collimated tubes still cannot effectively solve the problem of poor step coverage of large aspect ratio structures. In addition, there are also problems such as too slow deposition rate, low target utilization rate, and its processing and maintenance costs. are all very high, leading to problems such as increased coating costs.

In order to achieve the above objects and other related objects, the present invention provides a coating equipment that can improve deep hole filling, including: a cavity, a target carrier plate, a magnetic control component, a base and a straightener; the target carrier plate is located at The top of the cavity is used to fix the target, and the target is electrically connected to the first pulse power supply to provide positive and negative asymmetric bipolar pulses from the first pulse power supply; the magnetron assembly is located above the target carrier plate, The base is located in the cavity, and the corrector is located in the cavity and between the target and the base. There is a distance between the corrector and the base and is insulated from the cavity. The corrector is connected to the positive electrode of the external power supply. Connected with a positive bias, the corrector includes a plurality of correction units arranged at intervals. Each correction unit is a through-hole structure that penetrates up and down. The corrector is used to correct the inclination angle of the movement direction of the target cations.

Optionally, the negative pulse bias voltage provided by the first pulse power supply for sputtering the target material ranges from -800V to -100V, the positive pulse bias voltage ranges from 100V to 200V, and the pulse width and pulse width of the negative pulse bias voltage are The height is greater than the positive pulse bias voltage, and the frequency is 200Hz~20MHz.

Optionally, the external power supply electrically connected to the corrector includes several types of DC power supply, unipolar pulse power supply and DC superimposed pulse power supply, and is used to provide a constant positive bias voltage of 30V to 100V for the corrector and correction unit or Pulsed positive bias.

Optionally, the corrector includes a middle region and an edge region located outside the middle region. Adjacent regions are electrically insulated. Different positive bias voltages are applied to each region. The positive bias voltage gradually increases from the middle region to the edge region. big.

Optionally, the corrector includes a middle area and an edge area located outside the middle area, adjacent areas are electrically insulated, each area is applied with a positive bias voltage of the same size, and a plurality of convex patterns are provided on the internal side wall of the correction unit. , the shapes of the convex patterns include several types of cubes, hemispheres, cylinders and cones, and the height of the convex patterns gradually increases from the middle area to the edge area.

Optionally, the distance between the corrector and the base is greater than or equal to 40 mm.

Optionally, the distance between adjacent correction units is 2 mm to 10 mm.

Optionally, the aperture of the correction unit is 10 mm to 60 mm.

More optionally, the aperture of the correction unit is 20 mm to 40 mm.

Optionally, the aspect ratio of each correction unit is 1.5:1˜5:1.

Optionally, the upper aperture of the correction unit is greater than, equal to or smaller than the lower aperture.

Optionally, the aperture of the correction unit gradually decreases from the upper part to the middle, and the aperture remains unchanged from the middle to the lower part.

Optionally, the apertures of the upper and lower parts of the correction unit are larger than the aperture of the middle part.

Optionally, there are more than two correctors, and more than two correctors are stacked one above the other. Adjacent correctors are separated by an insulating ring with a through hole. The correction unit of each corrector is located above and below the through hole of the insulating ring. , each orthodontic device is connected to a different Connect to an external power supply and apply positive bias.

Optionally, the two or more correctors are stacked one above the other, the aperture of the correction unit remains unchanged, and the positive bias of each corrector gradually increases linearly from top to bottom.

Optionally, the two or more correctors are stacked one above the other, the aperture of the correction unit gradually decreases from top to bottom, and the positive bias of each corrector remains unchanged.

Optionally, the opening shape of the correction unit includes any one of a circle and a polygon, and the plurality of correction units are distributed in a densely packed array with the center of the cavity as the center.

Optionally, the base is connected to a radio frequency power supply, and the radio frequency power supply generates a radio frequency negative bias voltage, and the negative bias voltage ranges from -300V to -50V.

Optionally, the coating equipment further includes an upper baffle, a lower baffle and a shielding ring. One end of the upper baffle is close to the edge of the target, and the other end extends downward along the inner wall of the cavity to near the corrector. One end of the lower baffle is close to the edge of the end of the corrector away from the upper baffle, and the other end extends downward along the inner wall of the cavity to the periphery of the base. The shielding ring is fixed on the lower baffle and surrounds above the edge of the base.

Optionally, the coating equipment further includes a guide plate located in the cavity and between the corrector and the base, the guide plate is electrically insulated from the corrector, and the guide plate It includes a plurality of through-hole-shaped flow guide units distributed at intervals and a cross structure connected between the flow guide units. The flow guide units are surrounded by insulating materials, and the cross structure is made of conductive material. The structure is electrically connected to the second pulse power supply. The second pulse power supply provides positive and negative asymmetric bipolar pulses, in which the negative bias voltage provided is -150V~-50V, the positive pulse bias voltage provided is 20V~80V, and the negative pulse The pulse width and pulse height of the bias voltage are both larger than the positive pulse bias voltage.

Optionally, there is a gap between the guide plate and the corrector or they are separated by an insulating plate with a through hole.

The present invention also provides a coating method that can improve deep hole filling. The coating method uses the coating equipment described in any of the above solutions to perform deep hole filling.

As mentioned above, the coating equipment and method of the present invention that can improve deep hole filling have the following beneficial effects: the improved structural design of the present invention uses a corrector with a positive bias to correct the movement direction of the target cations, reducing the Its inclination angle with the vertical direction can greatly improve the bottom filling rate and side wall coverage rate of the deep hole structure. Compared with the deep hole filling equipment commonly used in the industry, the use of the coating equipment of the present invention for deep hole filling can greatly improve the deep hole filling rate. The bottom filling rate and sidewall coverage of the hole structure are increased by more than 70%. In particular, the present invention can significantly improve the filling uniformity of deep hole structures with a large aspect ratio (aspect ratio greater than 5:1, especially 8:1 or more), and can significantly increase the deposition rate. At the same time, the corrector of the present application is easy to process and has low processing cost. The correction unit has a long life and low maintenance cost, which helps to reduce the production cost of the semiconductor chip manufacturing plant and improve the economic benefits.

Description of the drawings

Figure 1 shows an exemplary cross-sectional structural diagram of a coating equipment provided by the present invention that can improve deep hole filling.

2 to 5 show structural schematic diagrams of the straightener of the coating equipment provided by the present invention in different examples.

Figures 6 and 7 show respectively a top view and a bottom view of the same orthosis.

Figure 8 shows a schematic diagram of the force exerted by the target cation above the correction unit.

Figure 9 shows a schematic diagram of the force exerted by the target cations in the correction unit.

Figure 10 shows a schematic diagram of the movement trajectory of target cations.

Figures 11 and 12 show schematic structural views of the baffle of the coating equipment provided by the present invention in different examples.

Component label description
11-cavity; 12-target material; 13-magnetic control component; 14-corrector; 141-correction unit; 15-base; 16-wafer; 17-upper baffle;
18-lower baffle; 19-shielding ring; 20-guide plate; 201-guide unit; 202-cross structure; 203-side wall.

Detailed ways

The following describes the embodiments of the present invention through specific examples. 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 embodiments. Various details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. When describing the embodiments of the present invention in detail, for convenience of explanation, the cross-sectional views showing the device structure are not partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual production.

For convenience of description, spatial relationship words such as "below", "below", "below", "below", "above", "on", etc. may be used herein to describe an element or element shown in the drawings. The relationship of a feature to other components or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientations depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, structures described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, as well as may include additional features formed between the first and second features. Embodiments between second features such that the first and second features may not be in direct contact.

It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner, and the drawings only show the components related to the present invention and do not follow the actual implementation of the component numbers, shapes and components. Dimension drawing, in actual implementation, the type, quantity and proportion of each component can be arbitrarily changed, and the component layout type may also be more complex. In order to keep the illustrations as concise as possible, not all structures are labeled in each drawing.

See Figure 1 through Figure 12.

As shown in Figures 1 to 12, the present invention provides a coating equipment that can improve deep hole filling, including: a cavity 11, a target carrier plate, a magnetic control assembly 13, a base 15 and a straightener 14; the target The material carrying plate is located at the top of the cavity 11 and is used to fix the target 12; the target 12 is electrically connected to the first pulse power supply (not shown) to provide positive and negative asymmetric bipolar pulses (not shown) from the first pulse power supply. The target material of traditional sputtering equipment is usually connected to a DC power supply or an RF power supply to generate a DC bias voltage or a radio frequency bias voltage. The reason why the RF power supply is not used in the present invention is that the inventor found through experiments that if the sputtering Using an RF power supply will generate a negative bias voltage on the target. When the sputtered target ions move from the negative bias target to the positive bias corrector, they move in the opposite direction of the electric field, and the ion kinetic energy will become smaller. , it will cause many low-energy ions to have their speed dropped to zero before they reach the upper opening of the correction unit, so the sputtering efficiency and filling effect of the RF power supply will become worse). The pulse frequency is preferably 200Hz ~ 20MHz (required It should be noted that when describing the numerical range in this specification, unless otherwise specified, all endpoint values are included). The preferred frequency is 100KHz ~ 800KHz. The pulse width and pulse height of the negative pulse bias are both larger than the positive pulse bias. voltage, and in a preferred example, the negative pulse bias voltage provided by the first pulse power supply for sputtering the target 12 ranges from -800V to -100V, and the positive pulse bias voltage ranges from 100V to 200V; The magnetron assembly 13 is located above the target 12 carrying plate, and may specifically include a magnetron and other structures. In addition, it may also include a cooling structure for cooling the target 12, such as a cooling water assembly; the base 15 is located in the cavity 11 , used to carry the wafer 16 to be coated. The base 15 can be an ordinary heating plate or an electrostatic adsorption plate. A heating and/or cooling unit can be provided in the base 15. The coating equipment usually includes the A support structure (not labeled) is connected to the bottom of the base 15. The support structure extends from the inside of the cavity 11 to the outside of the cavity 11. Source lines such as power lines and/or gas source lines can extend through the inside of the support structure. In the base 15 , the support structure can be connected to the driving structure to lift and/or rotate the base 15 when needed; the corrector 14 is located in the cavity 11 and is located in the target 12 There is a distance between the corrector 14 and the base 15, and the distance is preferably greater than or equal to 40 mm, and the corrector 14 is insulated from the cavity 11. For example, the corrector 14 can have a distance from the inner wall of the cavity 11 or An insulating layer is provided between the two, and the corrector 14 is electrically connected to the positive electrode of the external power supply. Therefore, the corrector 14 is made of a conductive material, such as a metal material, for example, it can be made of the cavity 11 or the baffle material mentioned later. The same, or its surface is plated with conductive material. The corrector 14 includes a plurality of correction units 141 arranged at intervals. Each correction unit 141 is a through-hole structure that penetrates up and down. The corrector 14 is used to correct the movement direction of the target cations and the movement direction of the target cations. The tilt angle in the vertical direction enables the target cations to move in the vertical downward direction into the deep holes on the wafer surface. Specifically, the structure of the corrector 14 can be shown with reference to FIGS. 2 to 7 , wherein FIG. 2 shows that the aspect ratio (the ratio of height to width, also known as the aspect ratio) is smaller (the aspect ratio is less than (equal to 2.5:1), Figure 3 is a circular corrector 14 with a small aspect ratio, Figure 4 is a square corrector 14 with a large aspect ratio (aspect ratio is greater than 2.5:1), Figure 5 is A circular corrector with a large aspect ratio14; corrective The outer contour of the straightener 14 is usually not smaller than the outline of the base 15, that is, try to ensure that the wafer 16 located on the base 15 is entirely covered by the orthographic projection of the straightener 14. The cross-section of each correction unit 141 of the straightener 14 is also That is, the opening shape may be circular, regular polygon including square, triangle and pentagon, or non-regular polygon. Each correction unit 141 is separated from the adjacent correction unit 141 by a side wall. The wall should be as thin as possible to reduce the deposition amount of target 12 particles on the upper surface of the straightener 14; preferably, the side wall thickness, that is, the distance between adjacent straightening units 141 is 2 mm to 10 mm (such as different If the thickness of the side walls between the correction units 141 is different, the distance refers to the thickness of the thinner part between two adjacent correction units 141). In order to improve the uniformity of the coating, the plurality of correction units 141 inside the corrector 14 are preferably distributed in a densely packed array with the center of the cavity 11 as the center outward. Therefore, triangles (not shown) or squares are used. The cross-section of the correction unit 141 is preferred. The height-to-width ratio of each correction unit 141 is preferably 1.5:1 and 5:1. The structural dimensions of different correction units 141 of the same corrector are preferably consistent, for example, each correction unit 141 The upper aperture is less than or equal to the lower aperture, that is, the apertures of each correction unit 141 can be the same size up and down, or can have a narrow top and wide structure as shown in Figures 6 and 7, that is, the top aperture of the correction unit 141 is smaller than the bottom aperture. , because the inventor found through experiments that if the correction unit 141 has a wide top and narrow structure with the upper opening larger than the lower opening, the repulsive force of the lower positive charges will be greater than the upper positive charges, which is not conducive to the downward acceleration of cations. Of course, in some examples, the upper aperture of the correction unit may also be larger than the lower aperture. And the inventor found through a large number of experiments that the aperture of the correction unit is preferably 10mm-60mm, and more preferably 20mm-40mm. The correction unit in this numerical range can play a very good correction effect on the target ions and avoid the target ions. Ion blockage correction unit. The size of the collimator unit in the prior art is generally 3-10mm, and the side walls of the collimator unit will be continuously plated with target particles during use (ions with a large tilt angle cannot pass through the collimator and fall. on the side wall), causing the aperture of the collimator tube to continuously shrink. When the collimator tube and target material are replaced for maintenance of the cavity, the aperture of the collimator tube will shrink by about 2mm. After long-term use, in the later stage, the initial size will be The aperture of the 3mm collimator unit will shrink to 1mm, and most of it will be blocked, making it difficult for target particles to pass; and the collimator unit with an initial size of 10mm will also shrink to 8mm by the end of use, a reduction of 20%. Problems such as decreased deposition rate and poor stability may also occur.

The working principle of the coating equipment provided by the present invention, especially the working principle of the corrector 14 is: when the target cations move downward through the correction unit 141, if the cations are not vertically downward but are farther from the vertical direction, If the tilt angle is large, the distance between the target cations and the two inner sides of the correction unit 141 will become unequal after moving for a certain distance, because the electrostatic force is inversely proportional to the square of the charge distance (according to the definition of the electrical warehouse force, two The magnitude of the interaction force between two stationary point charges Q1 and Q2 is proportional to the product of the charges Q1 and Q2, and inversely proportional to the square of the distance r between them. The direction of the force is along the line connecting them. Kinds of charges repel each other, and dissimilar charges attract each other). As shown in Figure 9, an inner side S1 of the closer (positively charged) correction unit 141 will exert a large horizontal repulsive force F1 on the target cations (initial velocity v), while the one farther away (same The other inner side S2 of the correction unit 141 (positively charged) will give positive The ion exerts a small horizontal repulsive force F2, and the resultant force of the two repulsive forces in the horizontal direction points to the farther inner side S2. Therefore, the cations will move along the trajectory shown by the dotted line in Figure 10, and finally pass through the correction unit 141. The bottom, that is, the cations will enter the deep hole structure on the surface of the wafer 16 at a small tilt angle to the vertical direction or in a direction close to the vertical downward direction. What needs special explanation here is that the working principle of the straightener 14 of the present invention is essentially different from the working principle of the collimation tube in the existing coating equipment. The existing collimating tubes all use high aspect ratio. The collimator units distributed in a honeycomb shape (for example, each collimator unit has a hexagonal structure) filter the target ions with a large inclination angle to the vertical direction. The target ions with a large inclination angle will eventually be attached to the honeycomb. On the side walls of the distributed collimator units, only some ions with small tilt angles will pass through the honeycomb-distributed collimator units and finally be deposited on the wafer surface. Therefore, the use efficiency of the target material is very low, and the sputtering rate is also low. is very low; at the same time, because a large number of target ions will be deposited on the side walls of the honeycomb-shaped collimator unit, the aperture of the honeycomb collimator unit will quickly shrink over time, and some holes will even be blocked in the later stage. If it is completely blocked, there will be a series of problems such as unstable sputtering rate and deep hole filling rate, short service life and high use cost. That is, the existing collimator relies on the physical barrier of the side wall to filter ions. Large-angle particles cannot pass through the collimator unit and eventually fall on the side wall of the collimator unit. Only those with small angles cannot pass through the collimator unit. Particles can be successfully deposited onto the wafer through the collimator. In addition, it is difficult for traditional collimator tubes to form a complete circular cross-section using a single honeycomb structure, so there will be some non-regular polygons including triangles and quadrilaterals with unequal side lengths on the edges of the collimator tube. Non-regular polygonal structures will be the first to be clogged due to excessive particle deposition during the process, thus affecting the stability of the sputtering rate and filling uniformity. The present invention relies on the repulsive force of the positive charges on the side wall of the correction unit to gradually correct the tilt angle of the cations (the angle changes from large to small), so that all target cations can pass through the correction unit, thus greatly improving the utilization of the target material. efficiency. At the same time, in the present invention, because the side wall of the correction unit is positively charged, when the target cations pass downward through the correction unit, they will not fall on the side wall due to the repulsive force from the side wall, which can greatly reduce the number of correction units. The amount of cations attached to the side wall, even if there is a non-regular polygonal structure on the edge of the corrector, due to the existence of repulsive force, the non-regular polygonal structure will not be blocked by cations, and it can also bring two major advantages: 1) Correction The aperture at the top of the unit will not shrink quickly due to the deposition of target cations (with a large tilt angle), which helps to maintain the stability of the target sputtering rate and the stability of the deep hole filling rate. 2) It can significantly extend the straightener The service life of the machine is reduced, the frequency of machine maintenance is reduced, the equipment productivity is increased, and the equipment usage cost is reduced.

The improved structural design of the present invention uses a corrector with a positive bias voltage to correct the movement direction of the target cations and reduce the inclination angle of the target cations to the vertical direction, which can greatly improve the bottom filling rate and side filling rate of the deep hole structure. Wall coverage rate: compared with the deep hole filling equipment commonly used in the industry, using the coating equipment of the present invention for deep hole filling can increase the bottom filling rate and side wall coverage rate of the deep hole structure by more than 70%. In particular, the present invention can significantly improve the filling uniformity of deep hole structures with a large aspect ratio (aspect ratio greater than 5:1, especially 8:1 or more), and can significantly increase the deposition rate. At the same time, the corrector of the present application is easy to process and has low processing cost. The correction unit has a long life and low maintenance cost, which helps to reduce the cost of semiconductor chip manufacturing plants. production costs and improve economic benefits.

As mentioned above, the rectifier 14 is connected to the positive pole of the external power supply, and the external power supply can be any one or more of a DC power supply, a unipolar pulse power supply, and a DC superimposed pulse power supply to serve as the rectifier 14 and the rectification unit 141 Provides a constant forward bias voltage of 30V to 100V or a pulsed forward bias voltage. After the external power supply is turned on, the inner surface of the correction unit 141 is positively charged and can be used to correct the tilt angle of the target cation movement direction.

In some examples, the corrector includes a middle area and an edge area located outside the middle area, that is, the corrector includes at least two areas, for example, the middle area is a circular area located in the center of the corrector, and the edge area surrounds the middle area. The annular area, the straightener can also be divided into more than 3 areas from the inside to the outside of the center of the straightener as needed. The adjacent areas are electrically insulated from each other. For example, vacuum gap insulation or insulating materials can be used for insulation; each area Positive bias voltages of different sizes can be applied to the regions, for example, the positive bias voltage gradually increases from the middle region to the edge region. The advantage of this structural design is that during the coating process, due to the different concentrations of sputtered particles from the target at the center of the wafer and the edge of the wafer, the tilt angle of the incident ions is also different. For conventional target magnet devices, Generally, the ion concentration in the center area of the wafer is high and the tilt angle is small, while the ion concentration in the edge area is low and the tilt angle is large, resulting in a better step coverage at the bottom of the deep hole structure in the center area of the wafer (for example, 21.2%), while the wafer center area has a low ion concentration and a small tilt angle. Rounded edges have poorer coverage (e.g. 12.6%). Therefore, in order to obtain consistent step coverage on the entire wafer, in the present invention, the positive bias voltage is gradually increased from the middle area to the edge area of the corrector, thereby enhancing the correction effect of the ion deflection angle in the edge area. As shown in Table 1, when the bias voltage in the edge area of the straightener is increased to 1.6 times that of the middle area, the step coverage at the wafer edge rapidly increases from the previous 12.6% to 18.3%, and the degree of improvement is close to 50%. Therefore, using This example helps improve the hole filling uniformity of film deposition.

Table 1 Deep hole filling improvement results corresponding to the corrector partition bias setting

In another example, for some target magnet devices, the magnetic field intensity at the edge of the target is significantly stronger than the magnetic field intensity at the center of the target. The ion concentration in the edge area is high and the tilt angle is small, resulting in a lower step coverage in the center area of the wafer. To achieve significantly better coverage than the wafer edge, in this case it is necessary to gradually reduce the forward bias voltage from the middle area to the edge area of the corrector, and instead strengthen the correction effect of the ion deflection angle in the middle area.

In other examples, the corrector 14 includes a middle area and an edge area located outside the middle area, that is, the corrector is also divided into at least two areas including a middle area and an edge area. electrically insulated from each other, A positive bias voltage of the same size is applied to each area, and multiple convex patterns are engraved on the internal side wall of the correction unit. The shapes of the convex patterns can be several types of cubes, hemispheres, cylinders and cones. For poor coverage of the wafer edge area, the height of the raised pattern can be gradually increased from the middle area of the aligner to the edge area. The increase in the convex height in the edge area will bring about a greater surface charge density, making the electric field intensity stronger, so this setting will better correct the ion deflection angle in the edge area. The advantage of this structural design compared with the aforementioned solution of using different forward bias voltages in different areas is that each area can use the same power supply to avoid mutual interference between multiple power supplies and help simplify the overall structure of the device.

In some examples, if a deep hole structure with a large aspect ratio is to be filled, for example, the aspect ratio is greater than or equal to 10, a better setting provided by this embodiment is that the aperture of the correction unit 141 is from the top down to the middle. Gradually decrease, until it reaches about half the depth of the correction unit (middle part) and then the aperture remains unchanged. The aperture is first reduced to gradually correct the tilt angle of the ion movement, but the kinetic energy of the ions will gradually decrease during this process. The subsequent aperture remains unchanged in order to maintain the kinetic energy of the ion movement and ensure that the ions have enough energy to pass through the correction unit and reach the crystal. round surface. Through such a setting, a good balance can be achieved between correcting the ion angle and maintaining the ion motion kinetic energy, achieving better filling effect.

In other examples, for filling deep hole structures with a large aspect ratio (for example, the same aspect ratio is greater than or equal to 10), there is another preferable setting, that is, the aperture of the correction unit 141 gradually increases from top to bottom. decreases, and the aperture gradually increases from top to bottom at about half the depth of the correction unit, that is, the apertures of the upper and lower parts of the correction unit are larger than the aperture of the middle part. The aperture of the correction unit is first reduced to gradually correct the tilt angle of the ion movement, but the kinetic energy of the ions will gradually decrease during this process. Then the aperture becomes larger, which can gradually increase the kinetic energy of the ion movement when the tilt angle of the ions is already very small, ensuring that the ions move It can have enough energy to pass through the correction unit and reach the wafer surface. It can also achieve a good balance between correcting the ion angle and maintaining the kinetic energy of the ion motion, thus achieving a better filling effect.

After sputtering starts, because the target cations leave the surface of the target 12 and move toward the downward direction of the top opening of the correction unit 141, they will receive an upward repulsive force from the upper surface of the correction unit 141 and the positive charges on both sides of the top opening of the correction unit 141. (Refer to Figure 8), so the speed of the target cations will gradually decrease, and the speed will decrease more as it goes downwards, until the cations enter the correction unit 141 for a certain distance. At this time, the cations are affected by the positive charges from above and below them. When the repulsive forces in opposite directions are basically equal in magnitude, the speed will no longer decrease. Because the cations sputtered by argon ions from the target 12 have different speeds and directions, the downward speed of the slower cations drops to zero before they enter the correction unit 141 . Therefore, in a further example provided by the present invention, in order to compensate for the decrease in the velocity of the initial target cations, a guide plate 20 is provided at the lower opening of the correction unit 141. The guide plate 20 is located in the cavity 11 and is located in the There is a distance between the straightener 14 and the base 15, and there is a distance from the base 15. There is a distance between the guide plate 20 and the straightener 14 or they are separated by an insulating plate with a through hole. The straightener 14 is electrically insulated, and the through holes of the guide plate and the through hole of the insulating plate should ensure that all the straightening units 141 are exposed to prevent blocking the ion travel path. Deflector The structure of the guide plate 20 can be seen in Figures 11 and 12. The overall appearance of the guide plate 20 can be the same as that of the corrector 14, for example, it is also an annular shape. The guide plate 20 is provided with a plurality of through holes, such as round holes, Square hole-shaped or other polygonal hole-shaped flow guide units 201 and a cross structure 202 connected between the flow guide units 201. The cross structure 202 is, for example, a cross ring structure or other similar structures. The guide plate 20 may be provided with Multiple square sidewalls 203 (refer to Figure 11) or circular sidewalls of multiple cross structures 202 are connected in series. The side walls 203 of the flow guide unit 201 are made of insulating materials, and only the cross structures 202 are made of conductive materials, such as metal aluminum. , copper and other materials, the guide plate 20 may also have no side walls (refer to Figure 12), because the side wall charges are not conducive to correcting the tilt angle of the cations. The guide plate 20 is connected to a second pulse power supply (not shown). The frequency of the second pulse power supply is preferably 200Hz to 20MHz, and more preferably 100KHz to 800KHz. The second pulse power supply provides positive and negative asymmetric bipolar sexual pulse, and the range of the negative bias voltage is preferably -150V ~ -50V, while the positive pulse bias voltage is preferably 20V ~ 80V, of which the negative pulse bias dominates and is used to increase the kinetic energy of the target cations, so the negative pulse bias The pulse width and pulse height of the pulse bias are both greater than the positive pulse bias. The short-term low-voltage positive pulse bias is used to prevent target cations from being adsorbed to the cross structure 202 of the guide plate 20 by the negative bias, and can also prevent Excessive forward bias reduces the downward velocity of cations. The first pulse power supply connected to the target 12 is used in conjunction with the guide plate 20. The positive bias pulse generated by the first pulse power supply will exert a downward repulsive force on the target cations, combined with the negative bias applied by the guide plate 20. The upward attraction and downward attraction help the target cations to basically maintain their original speed and enter smoothly downward into the deep hole structure of the wafer 16, which helps to further improve the deep hole filling efficiency and product yield.

In another example, if the guide plate 20 and the pulse power supply (the power supply used for sputtering the target 12) are not used, in order to ensure that the target cations will not suffer too much repulsion when they first enter the correction unit 141. The speed of the downward movement slows down, and multiple correctors 14 can also be used, that is, there are more than two correctors 14 stacked up and down. The multiple correctors 14 can adopt exactly the same structure, that is, different The apertures of the correcting units of the correctors remain unchanged, or the apertures are the same, and the correcting units 141 of different correctors 14 correspond up and down. Adjacent correctors 14 are separated by insulating rings with through holes, and the correcting units 141 of each corrector 14 The correction unit 141 is located above and below the through hole of the insulating ring (that is, the orthographic projection of the through hole is greater than or equal to the orthographic projection of all correction units 141 to ensure that the insulating ring does not block the ion traveling path and limits the ion traveling path within the insulating ring). The corrector 14 is connected to different external power supplies to apply positive bias voltage, and from top to bottom, the positive bias voltage of the external power supply connected to the corrector 14 gradually increases linearly (or the same corrector can be divided into two or more layers, each The two layers are separated by an insulating ring with openings. Each layer is connected to an independent power supply and controlled separately. The positive bias voltage increases linearly from top to bottom), which can also achieve a similar effect to the guide plate 20. In special cases, if the aspect ratio of the deep hole to be filled is extremely large (for example, greater than 15), the above-mentioned solution of stacking the guide plate 20 and multiple straighteners 14 on top of each other can be used at the same time.

In another example, multiple correctors 14 (more than two) can also be used. Multiple correctors 14 are stacked one on top of another, but the correction units 141 of different correctors 14 have different aperture sizes. For example, the correction units 141 of different correctors 14 The aperture gradually decreases from top to bottom, and the positive bias voltage of the external power supply connected to different correctors 14 can remain unchanged or can gradually increase from top to bottom. big. Such a setup is helpful for filling deep holes with extremely large aspect ratios (for example, greater than 15 or even greater than 20), because the gradually decreasing pore diameter from top to bottom helps to further reduce the tilt angle of the target cations, allowing more cations to Enter the deep hole in an almost vertical downward direction.

In a preferred example, the base 15 is connected to a radio frequency power supply. The radio frequency power supply generates a radio frequency negative bias voltage. The negative bias voltage ranges from -300V to -50V. The inclination angle has been reduced from the bottom of the corrector 14. The target cations will be further corrected under the action of the negative bias of the base 15, causing more target cations to enter the deep hole structure on the surface of the wafer 16 at a small tilt angle with the vertical direction or in a direction close to the vertical downward direction. Helps further improve coverage and filling uniformity of deep hole filling.

Although the present invention has used the corrector 14 and the guide plate 20 to correct the movement direction of the cations, some particles of the neutral target 12 may still be scattered around and cannot reach the surface of the wafer 16. Therefore, in order to prevent the contamination of the cavity 11, In the preferred example provided by the present invention, the coating equipment also includes an upper baffle 17, a lower baffle 18 and a shielding ring 19. One end of the upper baffle 17 is close to the edge of the target 12 but not in direct contact, and the other end is along the cavity. The inner wall of the body 11 extends downward to near the edge of the upper surface of the corrector 14 but not in direct contact, so that the upper and lower ends of the upper baffle 17 are respectively adjacent to the edges of the target 12 and the corrector 14 but remain electrically insulated. , one end of the lower baffle 18 is close to the edge of the end of the straightener 14 away from the upper baffle 17 but not in direct contact to ensure that the lower baffle 18 and the straightener 14 are electrically insulated, such as any two adjacent structures mentioned above. An insulating ring made of ceramic or quartz material can be placed between them to achieve insulation while making each structure more stable. The other end of the lower baffle 18 extends downward along the inner wall of the cavity 11 to the periphery of the base 15 (the upper baffle 17 Both the upper baffle 17 and the lower baffle 18 are hollow structures, with a target ion movement channel in the middle. The upper baffle 17 and the lower baffle 18 can be an integral structure and only separate a space for placing the corrector 14 between them. It can also be a split structure). The shielding ring 19 is fixed on the lower baffle 18 and is wound around the edge of the base 15 . The shielding ring 19 can prevent target ions from being deposited on the back side of the wafer 16 .

The coating equipment provided by the present invention can be used in conventional coating processes, but its advantages are particularly prominent when used to fill deep holes with a large aspect ratio.

The present invention also provides a coating method that can improve deep hole filling. The coating method is carried out by using the coating equipment described in any of the above solutions. Therefore, the aforementioned introduction to the coating equipment can be quoted here in full. For the sake of simplicity The purpose will not be described in detail. The main difference between the coating method using the coating equipment of the present invention and the prior art is that a straightener is used during the coating process, or a combination of a straightener and a deflector plate is used to correct the movement direction of the target cations, and the specific coating parameters It can be determined according to needs, and there are no strict restrictions on this. The coating method provided by the present invention is not only suitable for conventional thin film deposition, but also is particularly suitable for filling deep hole structures with a large aspect ratio (for example, the aspect ratio is greater than or equal to 5:1), which can greatly improve the deep hole filling efficiency. and yield, reducing production costs.

In summary, the present invention provides a coating equipment and method that can improve deep hole filling. The coating equipment includes: a cavity, a target carrier plate, a magnetic control component, a base and a straightener; the target carrier plate is located at the top of the cavity and is used to fix the target. The target is electrically connected to the first pulse power supply, so that the first pulse power supply provides positive and negative asymmetric bipolar pulses; the magnetic control component is located above the target carrier plate, the base is located in the cavity, and the correction The corrector is located in the cavity and between the target and the base. There is a distance between the corrector and the base and is insulated from the cavity. The corrector is electrically connected to the positive electrode of the external power supply and has a positive bias. The corrector includes a plurality of correction units arranged at intervals. Each correction unit is a through-hole structure that penetrates up and down. The corrector is used to correct the tilt angle of the target in the direction of cation movement. The improved structural design of the present invention uses a corrector with a positive bias to correct the movement direction of the target cations and reduce its inclination angle, which can greatly improve the bottom filling rate and side wall coverage of the deep hole structure, which is the same as commonly used in the industry. Compared with the deep hole filling equipment, using the coating equipment of the present invention for deep hole filling can increase the bottom filling rate and side wall coverage rate of the deep hole structure by more than 70%. In particular, the present invention can significantly improve the filling uniformity of deep hole structures with a large aspect ratio (aspect ratio greater than 5:1, especially 8:1 or more), and can significantly increase the deposition rate. At the same time, the corrector of the present application is easy to process and has low processing cost. The correction unit has a long life and low maintenance cost, which helps to reduce the production cost of the semiconductor chip manufacturing plant and improve the economic benefits. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

A kind of coating equipment that can improve deep hole filling, characterized by including: a cavity, a target carrier plate, a magnetic control component, a base and a straightener; the target carrier plate is located at the top of the cavity and is used to fix the target material, the target is electrically connected to the first pulse power supply, so that the first pulse power supply provides positive and negative asymmetric bipolar pulses; the magnetic control component is located above the target carrier plate, and the base is located in the cavity; The corrector is located in the cavity and between the target and the base. There is a distance between the corrector and the base and is insulated from the cavity. The corrector is electrically connected to the positive electrode of the external power supply and has a positive bias. The corrector includes a plurality of correction units arranged at intervals. Each correction unit is a through-hole structure that penetrates up and down. The corrector is used to correct the inclination angle of the movement direction of the target cations.
The coating equipment according to claim 1, characterized in that the negative pulse bias voltage provided by the first pulse power supply for sputtering the target material ranges from -800V to -100V, and the positive pulse bias voltage ranges from 100V to 200V. , the pulse width and pulse height of the negative pulse bias are larger than the positive pulse bias, and the frequency is 200Hz ~ 20MHz; the external power supply electrically connected to the corrector includes several types of DC power supply, unipolar pulse power supply and DC superimposed pulse power supply. , used to provide a constant positive bias voltage of 30V to 100V or a pulsed positive bias voltage in the corrector and correction unit.
The coating equipment according to claim 1, characterized in that the corrector includes a middle region and an edge region located outside the middle region, adjacent regions are electrically insulated, and each region applies forward bias voltages of different sizes, starting from the middle region. The positive bias voltage gradually increases from the area to the edge area; or the corrector includes a middle area and an edge area located outside the middle area, the adjacent areas are electrically insulated, and the same positive bias voltage is applied to each area, and the correction unit is internal Multiple convex patterns are provided on the side wall. The shapes of the convex patterns include several types of cubes, hemispheres, cylinders and cones. The height of the convex patterns gradually increases from the middle area to the edge area.
The coating equipment according to claim 1, characterized in that the distance between the corrector and the base is greater than or equal to 40 mm, the distance between adjacent correction units is 2 mm to 10 mm, and the aperture of the correction units is 10 mm to 60 mm. The aspect ratio of the correction unit is 1.5:1~5:1,
The coating equipment according to claim 4, characterized in that the aperture of the correction unit is 20mm-40mm, the aperture of the correction unit gradually decreases from the upper part to the middle, and the aperture remains unchanged from the middle to the lower part; or The apertures of the upper and lower parts of the correction unit are larger than the apertures of the middle part.
The coating equipment according to claim 1, characterized in that there are more than two correctors, and more than two correctors are stacked one on top of the other, and adjacent correctors are separated by an insulating ring with a through hole, and each corrector is The correction unit is located above and below the through hole of the insulating ring, and each corrector is connected to a different external power supply and is positively biased.
The coating equipment according to claim 6, characterized in that the two or more correctors are stacked one above the other, the aperture of the correction unit remains unchanged, and the positive bias of each corrector gradually increases linearly from top to bottom; or The two or more correctors are stacked one above the other, the aperture of the correction unit gradually decreases from top to bottom, and the positive bias of each corrector remains unchanged.
The coating equipment according to claim 1, characterized in that the opening shape of the correction unit includes any one of a circle and a polygon, and a plurality of correction units are densely packed outward with the center of the cavity as the center. Array distribution.
The coating equipment according to claim 1, characterized in that the base is connected to a radio frequency power supply, and the radio frequency power supply generates a radio frequency negative bias voltage, and the negative bias voltage ranges from -300V to -50V.
The coating equipment according to claim 1, characterized in that the coating equipment further includes an upper baffle, a lower baffle and a shielding ring. One end of the upper baffle is close to the edge of the target, and the other end is downward along the inner wall of the cavity. Extending to the vicinity of the corrector, one end of the lower baffle is close to the edge of the end of the corrector away from the upper baffle, and the other end extends downward along the inner wall of the cavity to the periphery of the base, and the shielding ring is fixed on on the lower baffle and around the edge of the base.
The coating equipment according to any one of claims 1 to 10, characterized in that the coating equipment further includes a guide plate located in the cavity and between the corrector and the base, the guide plate The flow plate is electrically insulated from the straightener. The flow guide plate includes a plurality of through-hole-shaped flow guide units distributed at intervals and a cross structure connected between the flow guide units. The flow guide unit is surrounded by an insulating material. The cross structure is made of conductive material, and the cross structure is electrically connected to a second pulse power supply. The second pulse power supply provides positive and negative asymmetric bipolar pulses, wherein the negative bias voltage provided is -150V~- 50V, the positive pulse bias provided is 20V ~ 80V, and the pulse width and pulse height of the negative pulse bias are larger than the positive pulse bias.
The coating equipment according to claim 11, characterized in that there is a gap between the guide plate and the straightener or they are separated by an insulating plate with a through hole.
A coating method that can improve deep hole filling, characterized in that the coating method is carried out using the coating equipment according to any one of claims 1 to 12.