Wafer coating device and coating method for improving step coverage

Abstract

The present application discloses a wafer coating device and a coating method for improving step coverage. The coating device includes a working chamber, a carrier, a first target material, a second target material and a third target material. The first target material is suspended above the carrier, and the second target material and the third target material are between the carrier and the first target material. The metal atoms sputtered by the first target material can well cover the plane part of the wafer and the bottom of the microhole. The metal atoms sputtered by the second target material and the third target material move toward the carrier along an oblique line. When approaching the carrier, the metal atoms will move downward along a parabola under the influence of the attraction of the carrier, thereby increasing the diversity of the incident angles of the metal atoms, which is beneficial for the metal atoms to cover the side walls of the microholes. Since the second target material and the third target material are arc-shaped structures and are arranged in the form of surrounding the wafer, the metal atoms sputtered by the second target material and the third target material can reliably and comprehensively cover the side walls of the microholes, thereby ensuring the step coverage of the wafer coating.

Description

Technical Field

[0001] The present application relates to the field of wafer coating technology, and in particular to a wafer coating device and a coating method for improving step coverage. Background Art

[0002] Step coverage is an indicator to measure the thickness loss of a film when it crosses steps or uneven areas on the wafer surface. It is usually expressed as the ratio of the film thickness at the step to the film thickness at the flat area. The closer this ratio is to 1, the better the coverage ability of the film at the step, that is, the film can more evenly cover the entire surface including the steps.

[0003] like Figure 1 As shown in the figure, the step coverage is defined as the ratio of the film thickness at the inner sidewall or bottom of the micropore to the film thickness at the top plane. Specifically, the ratio of the film thickness at b to the film thickness at a represents the bottom step coverage, the ratio of the film thickness at c to the film thickness at a represents the upper sidewall step coverage, the ratio of the film thickness at d to the film thickness at a represents the middle sidewall step coverage, and the ratio of the film thickness at e to the film thickness at a represents the lower sidewall step coverage.

[0004] In the actual semiconductor manufacturing process, good step coverage is crucial to ensure device performance and reliability.

[0005] In the prior art, the step coverage of wafers with micropores after coating is very low, often showing Figure 2 Even if a long-range directional sputtering chamber is used, the sidewall coverage is often significantly lower than the bottom, and the overall step coverage generally does not exceed 15%. Summary of the invention

[0006] The purpose of the present application is to overcome the deficiencies in the prior art and to provide a wafer coating device and a coating method that improve step coverage.

[0007] To achieve the above technical objectives, the present application provides a wafer coating device with improved step coverage, including: a working chamber for providing space for wafer coating; a carrier, arranged in the working chamber, for receiving the wafer; a first target, arranged in the working chamber and suspended directly above the carrier; a second target and a third target, arranged in the working chamber and between the carrier and the first target; wherein the second target and the third target are both arranged in an arc shape and are symmetrically arranged; after the carrier receives the wafer, a line connecting the center of the second target and the center of the wafer is arranged at an acute angle to the surface of the wafer, and a line connecting the center of the third target and the center of the wafer is also arranged at an acute angle to the surface of the wafer; the surface of the wafer has micropores; during the coating process, metal atoms sputtered from the first target can be deposited at the bottom of the micropores, and metal atoms sputtered from the second target and the third target can be deposited on the side walls of the micropores.

[0008] Furthermore, the surface of the carrier for receiving the wafer is arranged in a wavy shape; during the coating process, the wavy structure makes the potential distribution on the surface of the carrier uneven, and the charged metal atoms can change direction after approaching the carrier.

[0009] Furthermore, the center portion of the carrier is recessed downward to form a receiving groove, and the receiving groove is used to receive the wafer.

[0010] Furthermore, after the carrier receives the wafer, the line connecting the center of the second target material and the center of the wafer forms an angle of 45° with the surface of the wafer, and the line connecting the center of the third target material and the center of the wafer forms an angle of 45° with the surface of the wafer; and / or, after the carrier receives the wafer, the vertical distance between the center of the second target material and the wafer is 200 mm, and the vertical distance between the center of the third target material and the wafer is also 200 mm.

[0011] Furthermore, the wafer coating device for improving step coverage also includes a deflection adjustment mechanism, which is used to adjust the relative positions of the centers of the second target material and the third target material and the center of the wafer.

[0012] Furthermore, the wafer coating device for improving step coverage also includes a tilt changing mechanism, which is used to change the placement state of the wafer on the carrier so that the wafer is transformed from a horizontal state to an inclined state facing the second target or the third target.

[0013] Furthermore, the tilting and changing direction mechanism includes two groups of changing direction drive components, which are relatively arranged under the carrier; the changing direction drive components include a lifting drive component and a push rod, and the lifting drive component is used to drive the push rod to move in a vertical direction; a through hole is provided on the carrier, and the push rod can pass through the through hole and lift one side of the wafer; when one group of the changing direction drive components lifts one side of the wafer, the wafer tilts toward the second target material; when the other group of the changing direction drive components lifts the other side of the wafer, the wafer tilts toward the third target material.

[0014] Furthermore, the carrier includes a base and a movable panel, the movable panel is arranged on the base and is used to receive the wafer; a through hole runs through the base, and a push rod is connected to the movable panel through the through hole; the push rods of the two sets of direction-changing drive assemblies are arranged opposite to each other along the diameter direction of the wafer, and hanging rings are arranged on the tops of the push rods; two sets of buckle rings are arranged on the lower surface of the movable panel, and the two sets of buckle rings are also arranged opposite to each other along the diameter direction, and any hanging ring is buckled with a buckle ring; when lifting and changing direction, the push rod lifts the movable panel under the drive of the lifting drive component, so that the movable panel and the wafer thereon tilt to one side, and the hanging ring and the buckle ring can not only limit the movement direction of the movable panel and facilitate the resetting of the movable panel, but also compensate for the movement difference through relative movement.

[0015] The present application also provides a coating method, which can be implemented using the above-mentioned coating device, and the coating method includes the following steps: a carrier supports a wafer; an RF power of 3000W is input to the first target, and an RF power of 1000W is input to the second target and the third target; argon gas is introduced at a flow rate of 40sccm and a chamber pressure of 3.0mTorr; sputtering is performed for 300s to deposit a titanium thin film on the surface of the wafer.

[0016] Furthermore, the coating method also includes the following steps: the wafer on the carrier is tilted toward the second target by a tilting and changing mechanism; the first target maintains an RF power of 3000W, the second target maintains an RF power of 1000W, and the third target is powered off; argon gas is introduced at a flow rate of 40sccm and a chamber pressure of 3.0mTorr; sputtering for 150s; the wafer on the carrier is tilted toward the third target by a tilting and changing mechanism; the second target is powered off, the first target maintains an RF power of 3000W, and the third target inputs an RF power of 1000W; sputtering is continued for 150s; and coating is completed.

[0017] The present application provides a wafer coating device and a coating method for improving step coverage. The coating device includes a working chamber, a carrier, a first target material, a second target material and a third target material. The first target material is suspended directly above the carrier, and the second target material and the third target material are between the carrier and the first target material. The metal atoms sputtered by the first target material can well cover the planar part of the wafer and the bottom of the microholes. The metal atoms sputtered by the second target material and the third target material move toward the carrier along an oblique line. When approaching the carrier, the metal atoms are affected by the attraction of the carrier and move downward along a parabola, thereby increasing the diversity of the incident angles of the metal atoms, which is beneficial for the metal atoms to cover the side walls of the microholes. Since the second target material and the third target material are arc-shaped structures and are arranged in a form of surrounding the wafer, the metal atoms sputtered by the second target material and the third target material can reliably and comprehensively cover the side walls of the microholes, thereby ensuring the step coverage of the wafer coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of step coverage after coating when there are micropores on the surface of a wafer;

[0019] Figure 2 A schematic diagram of the step coverage of a common micro-hole after coating in the prior art;

[0020] Figure 3 A schematic diagram of the movement path of metal atoms sputtered from the side target when depositing on the wafer;

[0021] Figure 4 A schematic structural diagram of a wafer coating device for improving step coverage provided by the present application;

[0022] Figure 5 for Figure 4A schematic diagram of the structure of a carrier in a coating device shown;

[0023] Figure 6 A schematic diagram of the structure of a carrier, a second target material and a third target material provided in the present application;

[0024] Figure 7 A schematic diagram of a deflection adjustment mechanism provided in the present application;

[0025] Figure 8 A schematic diagram of a tilting direction changing mechanism provided in the present application causing a wafer to tilt toward a second target;

[0026] Fig. 9 for Figure 8 A schematic diagram showing a tilting direction changing mechanism causing the wafer to tilt toward the third target;

[0027] Fig.10 A schematic structural diagram of another tilt-changing mechanism, a carrier, a second target material and a third target material provided in the present application. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0029] The present application provides a wafer coating device with improved step coverage, comprising: a working chamber 100, for providing space for wafer coating; a carrier 210, disposed in the working chamber 100, for receiving the wafer; a first target 221, disposed in the working chamber 100 and suspended directly above the carrier 210; a second target 222 and a third target 223, disposed in the working chamber 100, and between the carrier 210 and the first target 221; wherein the second target 222 and the third target 223 are both arranged in an arc shape, and the two are arranged symmetrically.

[0030] For details, please refer to Figure 4 In the illustrated embodiment, the working chamber 100 includes a base 110, a connecting tube 120 and an upper cover 130. The top of the base 110 is open, the upper and lower ends of the connecting tube 120 are open and sealed on the base 110, the bottom of the upper cover 130 is open and sealed on the connecting tube 120, and the inner cavities of the base 110, the connecting tube 120 and the upper cover 130 are connected to form a coating chamber.

[0031] Continue to refer to Figure 4The left side of the base 110 is provided with a wafer inlet and outlet, and a wafer handling mechanism such as a robot can transfer the wafer to the coating chamber through the wafer inlet and outlet. The carrier 210 is arranged in the base 110 and faces the wafer inlet and outlet to facilitate receiving the wafer. The platform portion of the carrier 210 for receiving the wafer is arranged in a truncated cone shape to adapt to the configuration of the wafer.

[0032] Continue to refer to Figure 4 The inner cavity of the connecting cylinder 120 is arranged in a cylindrical shape, and the second target 222 and the third target 223 are extended along the inner cylinder wall of the connecting cylinder 120. The second target 222 and the third target 223 are both arranged in an arc-shaped strip shape, and the two are symmetrically arranged in the left-right direction; the longitudinal center axis of the carrier 210 is colinear with the symmetry axis of the second target 222 and the third target 223. The second target 222 and the third target 223 are arranged sequentially along a circumferential direction, and the carrier 210 is directly below the encirclement formed by the second target 222 and the third target 223, and the horizontal projection area of ​​the encirclement is larger than the surface area of ​​the carrier 210.

[0033] Continue to refer to Figure 4 The inner cavity of the upper cover 130 is also cylindrical, and the first target 221 is fixedly arranged on the inner top surface of the upper cover 130, suspended above the second target 222 and the third target 223, and facing the stage 210. The horizontal projection area of ​​the first target 221 is also larger than the surface area of ​​the stage 210.

[0034] Furthermore, an air inlet channel is provided on one side of the upper cover 130, and an air outlet channel is provided on the bottom surface of the base 110. The air inlet channel connects the coating chamber and the air supply equipment, and the air outlet channel connects the coating chamber and the exhaust equipment. The air supply equipment can pass the coating reaction gas into the coating chamber through the air inlet channel, and the exhaust equipment can extract the gas in the coating chamber through the air outlet channel; the air supply equipment and the exhaust equipment cooperate to maintain the intra-cavity air pressure required for the coating work.

[0035] Furthermore, the coating device also includes a power supply component, which is used to supply power to the first target material 221, the second target material 222 and the third target material 223. The targets can ionize the reaction gas after being energized; the power supply component is also used to supply power to the carrier 210. After being energized, the carrier 210 can generate a negative bias potential to attract positively charged metal atoms.

[0036] In a specific embodiment, the wafer transport mechanism delivers the wafer to be coated into the working chamber 100 through the wafer inlet and outlet. After the carrier 210 receives the wafer, the wafer transport mechanism withdraws and the working chamber 100 is closed. The gas supply device supplies the coating reaction gas into the working chamber 100 through the air inlet channel. The first target 221, the second target 222 and the third target 223 are energized. After the reaction gas is ionized, electrons bombard the target to blast out the metal atoms on the surface of the target. The carrier 210 is energized, the radio frequency energy induces bias, and a negative bias potential is generated, thereby attracting the blasted metal atoms to accelerate toward the carrier 210, and the metal atoms are deposited on the wafer surface to achieve coating.

[0037] The surface of the wafer has micropores. Since the first target 221 is suspended above the wafer, during the coating process, the metal atoms sputtered from the first target 221 will naturally move downward; when close to the wafer, the incident angle of most of the metal atoms is close to 90°, and they can well cover the flat part of the wafer and the bottom of the micropores (i.e. Figure 1 b of the micropore); a small number of metal atoms can be shot obliquely toward the wafer surface, but due to the influence of distance and acceleration, even if these metal atoms fall toward the micropore, they will mostly be concentrated on the upper side wall of the micropore (i.e. Figure 1 c of the micropores).

[0038] More specifically, after the carrier 210 receives the wafer, the line connecting the center of the second target 222 and the center of the wafer forms an acute angle with the surface of the wafer, and the line connecting the center of the third target 223 and the center of the wafer also forms an acute angle with the surface of the wafer.

[0039] In simple terms, when the target is symmetrical, its symmetry center is the center of the target described in this application. Figure 4 In the embodiment shown, the second target 222 and the third target 223 are rectangular structures extending from arcs, and the point where the lines connecting the two pairs of diagonals of the rectangle intersect is the center of the target. Similarly, the wafer is a disk structure, and the center of the disk is the center of the wafer.

[0040] Combined with reference Figure 6 In the illustrated embodiment, the second target 222 is arranged at the upper left of the carrier 210, and the third target 223 is arranged at the upper right of the carrier 210; after the carrier 210 receives the wafer, the surface of the wafer is horizontal; from left to right, the line connecting the center of the second target 222 and the center of the wafer extends downwardly at an angle A with the surface of the wafer being an acute angle; from right to left, the line connecting the center of the third target 223 and the center of the wafer extends downwardly at an angle B with the surface of the wafer being also an acute angle.

[0041] For the convenience of description, the second target 222 and the third target 223 are referred to as side targets. By ensuring that the angle between the line connecting the center of the side target and the center of the wafer and the horizontal plane is an acute angle, it can be ensured that the angle between each point on the side target and the horizontal plane connecting the center of the wafer is an acute angle. In this way, after the electrons bombard the side targets, the sputtered metal atoms can basically move toward the wafer along an inclined path; when the metal atoms fall toward the micropores, the natural inclined path makes it easier for them to deposit on the middle side wall (i.e. Figure 1 d of the micropores) and the lower sidewall (i.e. Figure 1 e) on the micropores in the medium.

[0042] Combined with reference Figure 3 In the illustrated embodiment, the second target 222 and the third target 223 are arranged above the wafer. After the electrons bombard the side targets, the sputtered metal atoms move along the oblique line toward the carrier 210. When approaching the carrier 210, the metal atoms will move downward along the parabola under the influence of the attraction of the carrier 210. This movement path further increases the diversity of the incident angles of the metal atoms, which is conducive to the metal atoms covering the side walls of the micropores. At the same time, since the second target 222 and the third target 223 are arc-shaped structures and are arranged in the form of surrounding the wafer, the metal atoms sputtered by the second target 222 and the third target 223 can reliably and comprehensively cover the side walls of the micropores.

[0043] In summary, the metal atoms sputtered by the first target 221 can be deposited at the bottom of the microhole, and the metal atoms sputtered by the second target 222 and the third target 223 can be deposited on the sidewalls of the microhole, thereby effectively ensuring the step coverage of the wafer coating.

[0044] Optionally, the surface of the carrier 210 for receiving the wafer is arranged to be wavy; during the coating process, the wavy structure makes the potential distribution on the surface of the carrier 210 uneven, and the charged metal atoms can change direction after approaching the carrier 210.

[0045] For details, please refer to Figure 5 In the illustrated embodiment, the surface of the carrier 210 is provided with a plurality of wave structures, and the plurality of wave structures are arranged side by side along a diameter direction of the carrier 210. The wave structure makes the surface of the carrier 210 bumpy. After the carrier 210 is powered on, the closer it is to the trough, the greater the electric potential, and the greater the attraction to the metal atoms. Therefore, as the metal atoms continue to approach the carrier 210, the metal atoms are more easily attracted to the trough; before being precipitated on the wafer, the metal atoms will deviate in the direction of the maximum electric potential; this directional deviation can change the incident angle of the metal atoms, thereby enriching the precipitation position of the metal atoms; if the trough is close to the micropore, the metal atoms are more likely to fall into the micropore and are more likely to be deposited on the side wall of the micropore after the directional deviation.

[0046] Optionally, the wave crest of the wave structure is arranged in an arc shape.

[0047] When the carrier 210 receives the wafer, the wave crest contacts and supports the wafer, and the arc configuration can avoid abrasion or damage to the back side process of the wafer.

[0048] Optionally, in any wave structure, the width of the corrugation gradually shrinks from the trough to the adjacent crest.

[0049] For details, please refer to Figure 5 In the illustrated embodiment, the corrugation width at the trough is the largest, and the troughs of any two adjacent wave structures are close to each other; the corrugation width at the crest is the smallest, and the crests of any two adjacent wave structures are spaced apart from each other; and the closer to the crest, the greater the spacing between two adjacent wave structures.

[0050] When the wave structure supports the wafer, the wafer is supported by the peak of the wave crest. At this time, the surroundings of the wave crest are all spacing areas. It is easy to understand that the larger the spacing area, the less the back of the wafer is touched, so the back process of the wafer is safer.

[0051] Optionally, the center portion of the carrier 210 is recessed downward to form a receiving groove, and the receiving groove is used to receive the wafer.

[0052] For details, please refer to Figure 5 In the illustrated embodiment, the stage 210 for supporting the wafer is arranged in a truncated cone shape, and the stage includes a circular center portion and an annular edge portion surrounding the center portion. The edge portion is higher than the center portion, and the annular ring surrounding the edge portion is the receiving groove.

[0053] The receiving groove can not only limit the placement position of the wafer to facilitate the loading and unloading of the wafer, but also prevent the wafer from being displaced or even falling during the movement of the carrier (such as lifting or rotating). When the coating device also includes a tilting direction-changing mechanism 400 (see below for details), the receiving groove can also provide support for the wafer in a tilted state and prevent the tilted wafer from falling off the carrier 210.

[0054] Optionally, the depth of the accommodating groove is not less than 0.5 mm.

[0055] In a specific embodiment, the edge of the carrier 210 is 1 mm higher than the center, that is, the depth of the receiving groove is 1 mm.

[0056] The depth of the receiving groove is made greater than the thickness of the wafer. When the wafer is vertically deflected by the tilting and changing mechanism 400 , the side of the wafer close to the rotation center can be well protected to prevent the wafer from falling off the carrier 210 .

[0057] In a specific embodiment, after the carrier 210 receives the wafer, the vertical distance between the center of the second target 222 and the wafer is 200 mm, and the vertical distance between the center of the third target 223 and the wafer is also 200 mm.

[0058] In a controlled variable experiment, the centers of the second target 222 and the third target 223 are at the same level, and the angle A and the angle B are both 45°. The height of the stage 210 or the side target is adjusted so that the vertical distance between the center of the second target 222 and the third target 223 and the wafer surface is 190 mm; the first wafer to be coated is input; the second target 222 and the third target 223 are input with 1000 W of RF power, and the first target 221 is input with 3000 W of RF power; argon gas with a flow rate of 40 sccm is introduced, and the chamber pressure is 3.0 mTorr, sputter for 300s to complete the first coating; adjust the height of the carrier 210 or the side target again so that the vertical distance between the center of the second target 222 and the third target 223 and the wafer surface is 200mm; input the second wafer to be coated, repeat the above coating operation to complete the second coating; adjust the height of the carrier 210 or the side target again so that the vertical distance between the center of the second target 222 and the third target 223 and the wafer surface is 210mm; input the third wafer to be coated, repeat the above coating operation to complete the third coating; adjust the height of the carrier 210 or the side target again so that the vertical distance between the center of the second target 222 and the third target 223 and the wafer surface is 220mm; input the fourth wafer to be coated, repeat the above coating operation to complete the fourth coating.

[0059] The following table shows the film step coverage at different vertical distances.

[0060]

[0061] It can be seen from the above table that when the vertical distance between the center of the side target and the wafer surface is 200mm, the hole filling step coverage of the coating is optimal.

[0062] In the above experiment, the corresponding step coverage after the second coating (vertical distance is 200mm) is shown in the following table.

[0063]

[0064] It can be seen from the table that the step coverage at each position of the micropore side wall is improved by the coating device provided by the present application.

[0065] Through similar controlled variable experiments, by changing the variable items to the angles of Angle A and Angle B, the optimal angle between the line connecting the center of the side target and the center of the wafer and the angle of the wafer surface can be obtained, thereby obtaining a better coating solution.

[0066] In a specific embodiment, after the carrier 210 receives the wafer, the line connecting the center of the second target 222 and the center of the wafer forms an angle of 45° with the surface of the wafer, and the line connecting the center of the third target 223 and the center of the wafer also forms an angle of 45° with the surface of the wafer.

[0067] In simple terms, experiments show that when the angle A and the angle B are 45°, the overall hole filling step coverage of the coating is optimal.

[0068] Optionally, the wafer coating device for improving step coverage provided in the present application further includes a lifting drive mechanism, and the lifting drive mechanism is used to drive the carrier 210 to move in the vertical direction.

[0069] The lifting drive mechanism can adopt any linear drive structure such as a cylinder or an electric cylinder. The stage 210 can be lifted and lowered to adjust the vertical distance between the wafer and the target. In normal operation, the stage 210 is directly opposite the wafer inlet and outlet at the first height position to facilitate the loading and unloading of the wafer; after the wafer is connected, the stage 210 is driven by the lifting drive mechanism to move to the second height position, at which time the wafer and the target are at the optimal vertical distance.

[0070] Optionally, the wafer coating device for improving step coverage provided in the present application further includes a deflection adjustment mechanism 300, which is used to adjust the relative positions of the centers of the second target 222 and the third target 223 and the center of the wafer.

[0071] By changing the relative positions of the centers of the second target 222 and the third target 223 and the center of the wafer through the deflection adjustment mechanism 300, the angle between the line connecting the center of the second target 222 and the center of the wafer and the surface of the wafer, the angle between the line connecting the center of the third target 223 and the center of the wafer and the surface of the wafer, and the angle A and the angle B can be changed.

[0072] In one embodiment, the second target 222 and the third target 223 can be moved closer to or farther from each other in the horizontal direction under the control of the deflection adjustment mechanism 300 .

[0073] For example, the deflection adjustment mechanism 300 includes two sets of horizontal drive components, and the horizontal drive components can adopt any linear drive structure such as a cylinder, an electric cylinder, etc. The second target 222 and the third target 223 are respectively connected to one set of horizontal drive components. The two sets of horizontal drive components work together to make the second target 222 and the third target 223 approach or move away from each other in the horizontal direction.

[0074] The second target 222 and the third target 223 are brought closer to each other in the horizontal direction, the horizontal distance between the center of the second target 222 and the center of the wafer is reduced, and the angle A is increased; the horizontal distance between the center of the third target 223 and the center of the wafer is reduced, and the angle B is increased. The second target 222 and the third target 223 are moved away from each other in the horizontal direction, the horizontal distance between the center of the second target 222 and the center of the wafer is increased, and the angle A is reduced; the horizontal distance between the center of the third target 223 and the center of the wafer is increased, and the angle B is reduced.

[0075] In another embodiment, the second target 222 and the third target 223 can change the target surface angle under the control of the deflection adjustment mechanism 300 .

[0076] For example, Figure 7 In the illustrated embodiment, the coating device includes two groups of deflection adjustment mechanisms 300, and the second target 222 and the third target 223 are respectively connected to one group of deflection adjustment mechanisms 300 and can change the target surface angle under the drive of the corresponding deflection adjustment mechanism 300. Specifically, a mounting hole 101 is provided on the cavity wall of the working cavity 100, and the mounting hole 101 penetrates the cavity wall in the horizontal direction; the deflection adjustment mechanism 300 includes: a roller 310, which is rotatably arranged in the mounting hole 101, and the second target 222 or the third target 223 is connected to the roller 310; a slider 320, which is slidably arranged in the mounting hole 101, and the roller 310 and the slider 320 are against each other; a slider driving member 330, which is arranged outside the working cavity 100 and is used to drive the slider 320 to move in the horizontal direction. When the target surface angle needs to be changed, the slider 320 is driven to translate in the left and right directions by the slider driving member 330 (which can adopt any linear driving structure such as a cylinder or an electric cylinder), and the slider 320 can drive the roller 310 to rotate through friction, and the roller 310 can drive the second target material 222 or the third target material 223 connected thereto to swing upward or downward around the rotating axis extending perpendicular to the paper surface.

[0077] Specifically, when the roller 310 rotates clockwise and the second target 222 or the third target 223 swings downward, the angle A or the angle B becomes smaller; when the roller 310 rotates counterclockwise and the second target 222 or the third target 223 swings upward, the angle A or the angle B becomes larger.

[0078] Optionally, an arc-shaped groove is provided on the hole wall of the mounting hole 101 facing the roller 310 , and a portion of the wheel surface of the roller 310 is confined in the arc-shaped groove.

[0079] The arc-shaped groove can define both the installation position of the roller 310 and the movement position of the roller 310 , so that the roller 310 can perform stable rotation.

[0080] Optionally, a horizontal guide groove is provided on the hole wall of the mounting hole 101 facing the slider 320 , and the slider 320 is slidably disposed in the horizontal guide groove.

[0081] Figure 7 In the embodiment shown, the horizontal guide groove is provided on the bottom surface of the mounting hole 101 and extends horizontally in the left-right direction. The two sides of the slider 320 in the width direction perpendicular to the paper are restricted in the horizontal groove. When the slider driving member 330 drives the slider 320 to move, the slider 320 can only translate left and right under the restriction of the horizontal guide groove.

[0082] The horizontal guide groove can play the role of guiding and positioning.

[0083] Optionally, a bellows 340 is provided between the slider driving member 330 and the working chamber 100 , and the bellows 340 can prevent air leakage from the mounting hole 101 .

[0084] The present application does not limit the specific configuration of the deflection adjustment mechanism 300 .

[0085] By providing the deflection adjustment mechanism 300 , the sizes of the angle A and the angle B can be easily changed, thereby facilitating the determination of the optimal coating position of the side target material.

[0086] The center positions of the second target 222 and the third target 223 can be adjusted independently. During the actual coating operation, the position of the side target can also be adjusted accordingly according to the coating uniformity. For example, the actual plasma distribution concentration in the coating chamber is high on the left and low on the right, resulting in the coating thickness on the right side of the wafer being less than that on the left, and the coating thickness on the right side wall of the microhole being greater than that on the left side; at this time, the center position of the third target 223 on the right side is adjusted so that the third target 223 is close to the wafer and the angle B is increased, which is beneficial to the coating of the right side surface and the left side wall of the microhole.

[0087] Optionally, the wafer coating device for improving step coverage provided in the present application also includes a tilt changing mechanism 400, which is used to change the placement state of the wafer on the carrier 210, so that the wafer is transformed from a horizontal state to an inclined state facing the second target material 222 or the third target material 223.

[0088] For details, please refer to Figure 8 In the illustrated embodiment, under the action of the tilt changing mechanism 400 , the wafer is deflected toward the second target 222 , and the front side of the wafer faces the second target 222 .

[0089] Combined with reference Fig. 9 In the illustrated embodiment, under the action of the tilt changing mechanism 400 , the wafer is deflected toward the third target 223 , and the front side of the wafer faces the third target 223 .

[0090] The wafer is transformed into a tilted state so that the micropores on the surface of the wafer can be better exposed within the action range of the side target material.

[0091] For example, when the wafer is in a horizontal state, the microholes on it extend vertically; when the microhole depth is large, it is difficult to ensure the step coverage of the middle sidewall and lower sidewall of the microhole, especially the corners of the lower sidewall and the bottom (i.e. Figure 1 The position of the middle micropore (the corner between e and b) is basically unable to be deposited by metal atoms conventionally. The wafer is deflected toward the second target 222 or the third target 223, and the micropore changes from a vertical state to a horizontal state. During this process, the side wall of the micropore gradually faces the side target from the state of facing away from the side target; after the wafer enters the tilted state, the micropore on it will also tilt toward the side target, so that the previously hidden middle side wall, lower side wall and bottom corner are exposed, which is conducive to the metal atoms sputtered by the side target to cover the deep part of the micropore.

[0092] In one embodiment, the tilt changing mechanism 400 is used to drive the carrier 210 to rotate around a horizontal axis, so that the carrier 210 and the wafer thereon are deflected toward the second target 222 or the third target 223 .

[0093] For example, the stage 210 includes a stage portion and an extension portion, the stage portion is used to support the wafer, one end of the extension portion is connected to the stage portion, and the other end extends outside the working chamber 100 to facilitate external cable connection; the center position of the stage portion is rotatably set on the extension portion through a rotating shaft, and the rotating shaft is extended in the horizontal direction. The tilting and changing mechanism 400 includes a motor and a transmission assembly, and the transmission assembly can be a worm gear, a gear set, etc. The motor is set outside the working chamber 100 and connected to the rotating shaft through the transmission assembly; when the wafer changes direction, the motor drives the rotating shaft to rotate through the transmission assembly, and the rotating shaft drives the stage portion to rotate, and the stage portion carries the wafer to deflect toward the side target; changing the driving direction of the motor can restore the stage portion carrying the wafer to a horizontal state or deflect toward another side target.

[0094] In another embodiment, the tilt changing mechanism 400 is used to cause the wafer to deflect in a certain direction.

[0095] For example, by lifting one side of the wafer from bottom to top with a pin, the front side of the wafer can be deflected toward the other side.

[0096] For another example, the two sides of the wafer in the diameter direction are fixed by a holder, and the holder is used to drive the wafer to deflect toward the desired side target.

[0097] In a specific embodiment, the tilting and changing mechanism 400 includes two groups of changing driving components, which are relatively arranged below the carrier 210; the changing driving components include a lifting driving member 410 and a lifting rod 420, and the lifting driving member 410 is used to drive the lifting rod 420 to move in a vertical direction; a through hole 210a is provided on the carrier 210, and the lifting rod 420 can pass through the through hole 210a and lift one side of the wafer; when one group of the changing driving components lifts one side of the wafer, the wafer tilts toward the second target material 222; when the other group of the changing driving components lifts the other side of the wafer, the wafer tilts toward the third target material 223.

[0098] For details, please refer to Figure 8 In the illustrated embodiment, the second target 222 is disposed at the upper left of the stage 210, and the third target 223 is disposed at the upper right of the stage 210; the tilting direction changing mechanism 400 includes two groups of direction changing driving components, the first group of direction changing driving components 400A is disposed at the left side below the stage 210, and the second group of direction changing driving components 400B is disposed at the right side below the stage 210. The lifting driving component 410 can adopt any driving structure such as a cylinder, an electric cylinder, etc.

[0099] Combined with reference Figure 4 The fixed end of the lifting drive member 410 is installed outside the working chamber 100 for easy installation and maintenance. The movable end of the lifting drive member 410 extends into the working chamber 100 and is connected to the mounting plate 430; two groups of lift rods 420 are arranged on the mounting plate 430, and the two groups of lift rods 420 are arranged at intervals along the circumferential direction; the lift rods 420 are added to stably lift one side of the wafer; a bellows is provided between the mounting plate 430 and the inner bottom wall of the working chamber 100, which can prevent air leakage and ensure the sealing of the chamber, and can also adapt to the lifting and lowering movement of the mounting plate 430.

[0100] Continue to refer to Figure 8 , the second set of direction-changing drive components 400B is started, and the lifting drive member 410 drives the mounting plate 430 and the lift rod 420 to rise, and the lift rod 420 can lift the right side of the wafer to deflect the wafer toward the second target 222. At this time, the left wall of the microhole is easier to deposit a thin film.

[0101] Combined with reference Fig. 9 The first set of direction-changing drive components 400A is started, and the lifting drive member 410 drives the mounting plate 430 and the lift rod 420 to rise, and the lift rod 420 can lift the left side of the wafer to deflect the wafer toward the third target 223. At this time, the right wall of the microhole is easier to deposit a thin film.

[0102] In another specific embodiment, the carrier 210 includes a base 211 and a movable panel 212, the movable panel 212 is arranged on the base 211 and is used to receive the wafer; the through hole 210a passes through the base 211, and the ejector rod 420 is connected to the movable panel 212 through the through hole 210a; the ejector rods 420 of the two groups of direction-changing drive assemblies are arranged opposite to each other along the diameter direction of the wafer, and the top of the ejector rod 420 is provided with a hanging ring 421; the lower surface of the movable panel 212 is provided with two groups of buckle rings 422, and the two groups of buckle rings 422 are also arranged opposite to each other along the diameter direction, and any hanging ring 421 is buckled with a buckle ring 422; when the lifting direction is changed, the ejector rod 420 is driven by the lifting drive member 410 to lift the movable panel 212, so that the movable panel 212 and the wafer thereon are tilted to one side, and the hanging ring 421 and the buckle ring 422 can not only limit the movement direction of the movable panel 212 and facilitate the resetting of the movable panel 212, but also compensate for the movement difference through relative movement.

[0103] For details, please refer to Fig.10 In the illustrated embodiment, the stage 210 includes a base 211 and a movable panel 212. The base 211 is roughly cylindrical and is provided with two two-stage through holes 210a. The through holes 210a vertically penetrate the base 211 and are spaced apart in the left-right direction. A receiving groove is provided at the center of the movable panel 212, and the wafer is confined in the receiving groove. Two sets of buckle rings 422 are provided on the bottom surface of the movable panel 212, and the two sets of buckle rings 422 are spaced apart in the left-right direction.

[0104] Continue to refer to Fig.10 The tilting direction changing mechanism 400 includes two groups of direction changing driving components, the first group of direction changing driving components 400C is arranged on the left side below the platform 210, and the second group of direction changing driving components 400D is arranged on the right side below the platform 210. A hanging ring 421 is respectively provided at the top of the two groups of top rods 420.

[0105] Continue to refer to Fig.10 The buckle ring 422 corresponds to the hanging ring 421 one by one, and a corresponding set of buckle rings 422 and hanging rings 421 are connected to each other. When the movable panel 212 and the wafer therein are in a horizontal state, the buckle ring 422 and the hanging ring 421 are in the upper hole of the through hole 210a with a larger aperture; the ejector rod 420 is inserted into the lower hole of the through hole 210a with a smaller aperture, and the lower hole extends vertically and can limit the movement direction of the ejector rod 420.

[0106] When the lifting direction changes, the lifting rod 420 rises under the drive of the lifting driving member 410, and after the hanging ring 421 on the lifting rod 420 abuts against the buckle ring 422 or the movable panel 212, the force-bearing side of the movable panel 212 can rise, thereby carrying the wafer to the other side. The buckle ring 422 and the hanging ring 421 on the other side that do not move vertically can prevent the movable panel 212 from falling off the base 211, and can also serve as a rotation center with a certain degree of freedom, so that the movable panel 212 carrying the wafer enters a tilted state.

[0107] The two sets of buckle rings 422 and the hanging ring 421 restrict each other, so that the movable panel 212 can only deflect to the left or right with the wafer, and it is not easy to cause problems such as deflection to the wrong direction, slipping, offset and tilting.

[0108] After the change of direction is completed, the top rod 420 is driven down by the lifting drive 410, and the hanging ring 421 on the top rod 420 pulls down the buckle ring 422, and the two can accurately and quickly return to the corresponding through hole 210a, thereby facilitating the movable panel 212 and the wafer to accurately and quickly restore the horizontal state.

[0109] In addition, the top rod 420 and the hanging ring 421 thereon move vertically, but the movable panel 212 and the buckle ring 422 thereon move rotationally, and the two move in different directions, resulting in a travel difference. Since the buckle ring 422 and the hanging ring 421 are annular structures, after the two are buckled, the gap between the rings and the form of the movable connection allow the buckle ring 422 and the hanging ring 421 to move relative to each other when the top rod 420 and the movable panel 212 move, so that the movement difference between the top rod 420 and the movable panel 212 can be well compensated.

[0110] The present application does not limit the specific configuration of the tilt changing mechanism 400 .

[0111] Optionally, the wafer is transformed from a horizontal state to an inclined state by a tilt changing mechanism 400; when the wafer is tilted toward the second target 222, the line connecting the center of the second target 222 and the center of the wafer and the wafer surface form a 60° angle; when the wafer is tilted toward the third target 223, the line connecting the center of the third target 223 and the center of the wafer and the wafer surface form a 60° angle.

[0112] In a controlled variable experiment, the centers of the second target 222 and the third target 223 are at the same level, the initial angle A and angle B are both 45°, and the vertical distance between the centers of the second target 222 and the third target 223 and the wafer surface is 200 mm. The wafer is tilted toward the second target 222 by the tilting and changing mechanism 400 to an angle A of 58°; the first wafer to be coated is input, the second target 222 and the third target 223 are input with 1000W RF power, the first target 221 is input with 3000W RF power, 40sccm argon gas is introduced, and the chamber pressure is 3.0 mTorr, sputter for 150s, then, the wafer is tilted toward the third target 223 to an angle B of 58° through the tilting and changing mechanism 400, and sputtering is continued for 150s to complete the first coating; the second wafer to be coated is input, the angle A and the angle B are adjusted to 60° in turn, and the above coating operation is repeated to complete the second coating; the third wafer to be coated is input, the angle A and the angle B are adjusted to 62° in turn, and the above coating operation is repeated to complete the third coating; the fourth wafer to be coated is input, the angle A and the angle B are adjusted to 64° in turn, and the above coating operation is repeated to complete the fourth coating.

[0113] The following table shows the film step coverage when the line between the center of the side target and the center of the wafer is at different angles to the wafer surface.

[0114]

[0115] It can be seen from the above table that when the line between the center of the side target and the center of the wafer is at an angle of 60° to the wafer surface, the hole filling step coverage of the coating is optimal.

[0116] The present application also provides a coating method, which can be implemented by using the above coating device. The coating method comprises the following steps:

[0117] The carrier 210 receives the wafer;

[0118] The first target 221 is input with a radio frequency power of 3000 W, and the second target 222 and the third target 223 are input with a radio frequency power of 1000 W;

[0119] Argon gas was introduced at a flow rate of 40 sccm and the chamber pressure was 3.0 mTorr;

[0120] Sputtering lasts for 300 seconds to deposit a titanium film on the wafer surface.

[0121] The RF power of the first target 221 is high, which can ensure that the entire surface of the wafer is fully coated. The RF power of the second target 222 and the third target 223 is low, which can avoid co-frequency interference and improve the hole filling effect in a targeted manner.

[0122] Furthermore, the coating method provided by the present application also includes the following steps:

[0123] The wafer on the stage 210 is tilted toward the second target 222 by the tilt changing mechanism 400;

[0124] The first target 221 maintains a radio frequency power of 3000 W, the second target 222 maintains a radio frequency power of 1000 W, and the third target 223 is powered off;

[0125] Argon gas was introduced at a flow rate of 40 sccm and the chamber pressure was 3.0 mTorr;

[0126] Sputtering for 150 seconds;

[0127] The wafer on the stage 210 is tilted toward the third target 223 by the tilt changing mechanism 400;

[0128] The second target 222 is powered off, the first target 221 maintains a RF power of 3000W, and the third target 223 inputs a RF power of 1000W;

[0129] Continue sputtering for 150 seconds;

[0130] Finish coating.

[0131] Specifically, after the carrier 210 receives the wafer, the wafer is kept in a horizontal state, and the three targets work together and sputter for 300 seconds; then, the wafer is first deflected toward the second target 222, and the second target 222 is sputtered for 150 seconds, with the focus on coating the left side wall of the micropore; then, the wafer is deflected toward the third target 223, and the third target 223 is sputtered for 150 seconds, with the focus on coating the right side wall of the micropore.

[0132] By deflecting the wafer, the filling coverage effect of the microhole sidewalls and corners can be enhanced.

[0133] During the deflection hole filling process, the third target 223 or the second target 222 on the opposite side is powered off, which can also prevent a large number of metal atoms from falling onto the back of the wafer or the bottom of the chamber.

[0134] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A wafer coating device for improving step coverage, characterized in that: include: A working chamber (100), used to provide space for wafer coating; A carrier (210) is disposed in the working chamber (100) and is used to receive a wafer; A first target material (221) is disposed in the working chamber (100) and suspended directly above the carrier (210); The second target (222) and the third target (223) are arranged in the working chamber (100) and between the carrier (210) and the first target (221); the second target (222) and the third target (223) are both arranged in an arc shape and are symmetrically arranged; An inclination changing mechanism (400), the inclination changing mechanism (400) being used to change the placement state of the wafer on the carrier (210), so that the wafer is changed from a horizontal state to an inclined state facing the second target material (222) or the third target material (223); After the carrier (210) receives the wafer, a line connecting the center of the second target (222) and the center of the wafer is arranged at an acute angle to the surface of the wafer, and a line connecting the center of the third target (223) and the center of the wafer is also arranged at an acute angle to the surface of the wafer; The surface of the wafer has micropores; During the coating process, the metal atoms sputtered by the first target material (221) can be deposited on the bottom of the microhole, and the metal atoms sputtered by the second target material (222) and the third target material (223) can be deposited on the sidewalls of the microhole; Wherein, the tilting direction-changing mechanism (400) comprises two groups of direction-changing drive components, and the two groups of direction-changing drive components are arranged opposite to each other below the carrier (210); The direction-changing drive assembly comprises a lifting drive member (410) and a push rod (420), wherein the lifting drive member (410) is used to drive the push rod (420) to move in a vertical direction; The carrier (210) is provided with a through hole (210a), and the ejector rod (420) can pass through the through hole (210a) and lift up one side of the wafer; When one group of the direction-changing drive components lifts up one side of the wafer, the wafer tilts toward the second target material (222); When another group of the direction-changing driving components lifts up the other side of the wafer, the wafer tilts toward the third target material (223); The carrier (210) comprises a base (211) and a movable panel (212); the movable panel (212) is arranged on the base (211) and is used to receive a wafer; The through hole (210a) passes through the base (211), and the top rod (420) is connected to the movable panel (212) through the through hole (210a); The push rods (420) of the two groups of the direction-changing drive assemblies are arranged opposite to each other along the diameter direction of the wafer, and the top ends of the push rods (420) are provided with hanging rings (421); Two groups of buckle rings (422) are provided on the lower surface of the movable panel (212), and the two groups of buckle rings (422) are also arranged opposite to each other along the diameter direction, and any one of the hanging rings (421) is buckled with one of the buckle rings (422); When the lifting direction changes, the lifting rod (420) lifts up the movable panel (212) under the drive of the lifting driving member (410), so that the movable panel (212) and the wafer thereon are tilted to one side, and the hanging ring (421) and the buckle ring (422) can not only limit the movement direction of the movable panel (212) and facilitate the resetting of the movable panel (212), but also compensate for the movement difference through relative movement.

2. The wafer coating device for improving step coverage according to claim 1, characterized in that: The surface of the carrier (210) for receiving the wafer is arranged in a wavy shape; During the coating process, the wave structure causes the electric potential on the surface of the carrier (210) to be unevenly distributed, and charged metal atoms can change direction when approaching the carrier (210).

3. The wafer coating device for improving step coverage according to claim 1 or 2, characterized in that: The center portion of the carrier (210) is recessed downward to form a receiving groove, and the receiving groove is used to receive the wafer.

4. The wafer coating device for improving step coverage according to claim 1, characterized in that: After the carrier (210) receives the wafer, a line connecting the center of the second target (222) and the center of the wafer and the surface of the wafer form an angle of 45°, and a line connecting the center of the third target (223) and the center of the wafer and the surface of the wafer also form an angle of 45°; And / or, after the carrier (210) receives the wafer, the vertical distance between the center of the second target (222) and the wafer is 200 mm, and the vertical distance between the center of the third target (223) and the wafer is also 200 mm.

5. The wafer coating device for improving step coverage according to claim 1, characterized in that: It also comprises a deflection adjustment mechanism (300), wherein the deflection adjustment mechanism (300) is used to adjust the relative positions of the centers of the second target material (222) and the third target material (223) and the center of the wafer.

6. A coating method, characterized in that: The coating method can be implemented by using the coating device according to any one of claims 1 to 5, and the coating method comprises the following steps: The carrier (210) receives the wafer; The first target (221) inputs a radio frequency power of 3000 W, and the second target (222) and the third target (223) input a radio frequency power of 1000 W; Argon gas was introduced at a flow rate of 40 sccm and the chamber pressure was 3.0 mTorr; Sputtering lasts for 300 seconds to deposit a titanium film on the wafer surface.

7. The coating method according to claim 6, characterized in that: The following steps are also included: The wafer on the carrier (210) is tilted toward the second target material (222) by means of a tilting direction changing mechanism (400); The first target (221) maintains a radio frequency power of 3000 W, the second target (222) maintains a radio frequency power of 1000 W, and the third target (223) is powered off; Argon gas was introduced at a flow rate of 40 sccm and the chamber pressure was 3.0 mTorr; Sputtering for 150 seconds; The wafer on the carrier (210) is tilted toward the third target material (223) by means of the tilt direction changing mechanism (400); The second target (222) is powered off, the first target (221) maintains a radio frequency power of 3000 W, and the third target (223) inputs a radio frequency power of 1000 W; Continue sputtering for 150 seconds; Finish coating.

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