Stress-free polishing device and stress-free polishing method

Abstract

A stress-free polishing device, comprising: a fixture (11) for holding a substrate (w) and driving the substrate to rotate, wherein an electrically conductive ring (111) is provided on the fixture, and the electrically conductive ring is in contact with an edge of the substrate; a nozzle (12) arranged below the fixture and used for spraying polishing slurry onto the substrate, the nozzle and the substrate being capable of performing relative linear motion in a horizontal direction; and a control module configured to: acquire the current distance (r) between a projection point of the center of the nozzle (12) on a plane where the substrate (w) is located and the center of the substrate, and, if the substrate is currently located above the nozzle, adjust a current electric current magnitude and / or relative movement speed between the nozzle and the substrate on the basis of the distance. The device can adjust the removal rate of a metal layer in each region of the substrate and improve polishing uniformity. The present application also relates to a stress-free polishing method.

Description

Stress-free polishing apparatus and polishing method TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing equipment, and in particular, to a stress-free polishing apparatus and polishing method. BACKGROUND

[0002] With the gradual popularization of fan-out advanced packaging technology and the change of substrate material, the application of square substrates is increasing. Generally, after the copper deposition process of the metal layer is completed, an additional planarization process is needed to remove the excess metal layer or optimize the bump height and flatness. In the prior art, a stress-free polishing process is usually used, specifically, the substrate is fixed on a clamp, the clamp moves horizontally while rotating, and the polishing liquid is sprayed on the substrate through a nozzle to react with the metal layer on the surface of the substrate. During the continuous polishing process, the metal layer on the surface of the substrate is removed.

[0003] However, in the actual process, when polishing the edges of the square substrate, only the four corner areas can receive the polishing liquid, and the current is easily concentrated in the four corner areas of the square substrate, resulting in an excessively high polishing rate in the corner areas, which affects the polishing uniformity of the substrate. SUMMARY

[0004] The purpose of the present application is to provide a stress-free polishing apparatus and polishing method to solve the problem of excessively high polishing rate in the corner areas of the square substrate in the prior art.

[0005] To achieve the above and other related purposes, the present application provides a stress-free polishing apparatus, comprising:

[0006] A clamp for holding and rotating the substrate, the clamp is provided with a conductive ring in contact with the edge of the substrate;

[0007] A nozzle is arranged below the clamp for spraying polishing liquid on the substrate, the nozzle and the substrate can move linearly relative to each other in the horizontal direction;

[0008] A control module configured to obtain the distance between the projection point of the center of the nozzle on the plane where the substrate is located and the center of the substrate, and if the substrate is currently located above the nozzle, adjust the current size and / or the relative movement speed of the nozzle and the substrate according to the distance.

[0009] Further, the material of the clamp includes a conductive metal.

[0010] Further, the cross-sectional shape of the nozzle is square.

[0011] Furthermore, the clamp includes an inner edge for supporting the substrate, and the conductive ring is disposed on the inner edge.

[0012] Furthermore, a sealing ring is provided on the inner edge of the clamp, and the sealing ring covers the conductive ring.

[0013] Furthermore, it also includes a pressure plate disposed between the back of the clamp and the substrate.

[0014] Furthermore, it also includes an angle sensor for detecting the angle of rotation of the substrate; the control module is also configured to: when the projection point of the center of the nozzle on the plane of the substrate is located in the region between the inscribed circle and the circumscribed circle of the substrate, the control module turns on the control current when the apex corner of the substrate rotates to above the nozzle, and turns off the control current when the apex corner of the substrate moves away from above the nozzle.

[0015] Furthermore, the control module is also configured to: control the nozzle or substrate to perform uniform linear motion, and ensure that the distance between the projection point of the center of the nozzle on the plane of the substrate and the center of the substrate, and the magnitude of the current satisfy the following formula:

[0016] When 0≤r≤b, I=D*πb 2 ;

[0017] When b < r < a, I = D*[πr] 2 -π(rb) 2 ];

[0018] when When the apex of the substrate rotates to above the nozzle, I = D*[πr 2 -π(rb) 2 When the apex angle of the substrate is not above the nozzle, I = 0;

[0019] Where r is the distance between the projection point of the center of the nozzle on the plane of the substrate and the center of the substrate, a is half the side length of the substrate, b is half the side length of the area on the substrate where the nozzle sprays polishing liquid, and D is the current density.

[0020] Furthermore, the control module is configured to: maintain a constant current magnitude, and ensure that the distance between the projection point of the nozzle center on the plane of the substrate and the center of the substrate, and the relative moving speed of the nozzle and the substrate satisfy the following formula:

[0021] When 0 ≤ r ≤ b, V = V0;

[0022] When b < r < a

[0023] When ,

[0024] wherein r is the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate, V0 is a preset initial speed, a is half of the side length of the substrate, b is half of the side length of the area on the substrate where the polishing liquid is sprayed by the spray head; the circle formed by the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate as the center and the distance between them as the radius intersects the side of the substrate at multiple intersection points, and θ is the included angle between the line connecting one of the intersection points and the center of the substrate and the line connecting the vertex adjacent to the intersection point and the center of the substrate.

[0025] Further, the control module is configured to control the substrate to remain stationary in the horizontal direction and control the spray head to move linearly in the horizontal direction.

[0026] Further, the control module is configured to control the position of the spray head to be fixed and control the clamp to drive the substrate to move linearly in the horizontal direction.

[0027] The application also provides a stress-free polishing device, comprising:

[0028] a clamp for holding a substrate, wherein the area of the clamp other than the area where the substrate is placed is provided with a sacrificial ring, the material of the sacrificial ring is the same as the metal on the surface of the substrate, and the clamp is used to drive the substrate and the sacrificial ring to rotate;

[0029] a spray head arranged below the clamp and used for spraying a polishing liquid to the substrate; the spray head and the substrate can move linearly relative to each other in the horizontal direction;

[0030] an auxiliary spray head arranged below the clamp and relatively stationary with the substrate in the horizontal direction, and used for spraying a polishing liquid to the outer edge of the sacrificial ring.

[0031] Further, a control module is further included, which is configured to obtain the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate, and adjust the current size and / or the relative moving speed of the spray head and the substrate according to the distance.

[0032] Further, the clamp is a vacuum clamp.

[0033] Further, the clamp is in the shape of a circle concentric with the substrate, and the diameter of the clamp is greater than the length of the diagonal of the substrate.

[0034] Further, the projection of the auxiliary nozzle and the nozzle on the substrate do not coincide at all during the horizontal movement of the clamp.

[0035] Further, the control module is further configured to control the nozzle or the substrate to move at a constant speed in a straight line, and make the distance between the projection point of the center of the nozzle on the plane where the substrate is located and the center of the substrate and the current size satisfy the following formula:

[0036] When 0≤r≤b, I=D*πb 2 ;

[0037] When , I=D*[πr 2 -π(r-b) 2 ];

[0038] Wherein, a is half of the side length of the substrate, b is half of the side length of the area where the nozzle sprays polishing liquid on the substrate, and D is the current density.

[0039] Further, the control module is further configured to control the current size to be constant, and make the distance between the projection point of the center of the nozzle on the plane where the substrate is located and the center of the substrate and the relative movement speed of the nozzle and the substrate satisfy the following formula:

[0040] When 0≤r≤b, V=V0;

[0041] When ,

[0042] Wherein, V0 is a preset initial speed, a is half of the side length of the substrate, and b is half of the side length of the area where the nozzle sprays polishing liquid on the substrate.

[0043] Further, the cross section of the nozzle is square.

[0044] The application also provides a stress-free polishing method, comprising:

[0045] Obtaining the distance between the projection point of the center of the nozzle on the plane where the substrate is located and the center of the substrate;

[0046] Adjusting the current size and / or the relative movement speed of the nozzle and the substrate according to the distance.

[0047] Further, it also comprises detecting the angle of the rotation of the substrate, controlling the current to be turned on when the projection point of the center of the nozzle on the plane where the substrate is located is located in the area between the inscribed circle and the circumscribed circle of the substrate and the top angle of the substrate rotates above the nozzle, and controlling the current to be turned off when the top angle of the substrate leaves above the nozzle.

[0048] Further, the application is applied to semiconductor processes, including any one or more of TGV process, double damascene process, copper pillar bump technology and RDL local via process.

[0049] As described above, the application provides a stress-free polishing device and polishing method, having the following beneficial effects: with the relative horizontal movement of the clamp and the substrate, the current size and / or the relative moving speed of the substrate and the showerhead are calculated and adjusted according to the distance between the projection point of the center of the showerhead on the plane where the substrate is located and the center of the substrate, so as to adjust the removal rate of the metal layer of each region of the substrate, thereby improving the polishing uniformity.

[0050] SUMMARY

[0051] The features and advantages of the present application are further described by the following embodiments and drawings.

[0052] Fig. 1 shows a schematic diagram of a stress-free polishing device in Embodiment One of the present application;

[0053] Fig. 2 shows another schematic diagram of a stress-free polishing device in Embodiment One of the present application;

[0054] Fig. 3 shows a schematic diagram of the projection of the showerhead on the substrate in Embodiment One of the present application;

[0055] Fig. 4 shows another schematic diagram of the projection of the showerhead on the substrate in Embodiment Two of the present application;

[0056] Fig. 5 shows a schematic diagram of a stress-free polishing device in Embodiment Four of the present application;

[0057] Fig. 6 shows another schematic diagram of a stress-free polishing device in Embodiment Four of the present application;

[0058] Fig. 7 shows a schematic diagram of the projection of the showerhead and the auxiliary showerhead on the substrate in Embodiment Five of the present application.

[0059] Preferred embodiments of the present application

[0060] The specific embodiments of the present application are described below with reference to the drawings, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the present specification. The present application can also be implemented or applied by different specific embodiments, and the details in the present specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0061] It should be noted that the diagrams provided in the embodiments are only schematic and that the drawings for the purpose of an illustration only and that the actual implementation of the application can vary depending on the implementation. The same reference signs are used in different drawings to denote the same or similar components.

[0062] Embodiment One

[0063] Referring to FIG. 1 and FIG. 2, the structure of a stress-free polishing device according to Embodiment One of the present application is disclosed, which is based on the principle of electrochemical polishing of the substrate w. The device includes a clamp 11 holding the substrate w and an electrochemical polishing liquid spray head 12 arranged below the clamp 11. The spray head 12 is electrically connected to the negative electrode of a power supply 13, and the polishing liquid is sprayed from the spray head 12 and sprayed on the surface of the substrate w. The clamp 11 has an inner edge (not shown in the figure) supporting the substrate w. The substrate w is placed horizontally with the front surface facing downward, and the outer edge of the substrate w is placed on the inner edge of the clamp 11. The substrate w is electrically connected to the positive electrode of the power supply 13. Specifically, the material of the clamp 11 includes a conductive metal, and the clamp 11 is connected to the positive electrode of the power supply 13. The inner edge of the clamp 11 is provided with a conductive ring 111, and the outer edge of the substrate w is in contact with the conductive ring 111. The conductive ring 111 is electrically connected to the substrate w through the polishing liquid. The clamp 11 is also provided with a sealing ring 112 on the inner edge, which covers the conductive ring 111. The area covered by the sealing ring 112 does not contact the polishing liquid, so as to ensure that the current passes through the substrate w entirely, and the current is not shunted by other metals such as the clamp 11.

[0064] The substrate w involved in the present application can be non-circular. Taking a square substrate as an example, the conductive ring 111 and the sealing ring 112 can be square, and their shape and size are adapted to the substrate w. The present application is described with the substrate w being square, which does not limit the shape of the substrate.

[0065] The device also includes a pressing plate 14 arranged between the clamp 11 and the back surface of the substrate w. When the substrate w is placed in the clamp 11, a certain pressure is applied to the pressing plate 14, so that the pressing plate 14 is pressed down, ensuring that the substrate w remains relatively stationary with the clamp 11 during the process.

[0066] The top center of the clamp 11 is provided with a rotating shaft 15, which can rotate around its own center, thereby driving the clamp 11 to rotate. The device further comprises a crossbeam (not shown in the figure) arranged above the clamp 11, and the rotating shaft 15 is installed on the crossbeam. The rotating shaft 15 can be fixedly installed on the crossbeam, and the crossbeam can move linearly in the horizontal direction, thereby driving the clamp 11 to move linearly in the horizontal direction; or the rotating shaft 15 can be slidably installed on the crossbeam, thereby driving the clamp 11 to move linearly in the horizontal direction. The arrow in FIG. 1 represents the linear movement of the clamp 11 in the horizontal direction, and the arrow direction is only an example and does not limit the movement direction of the clamp 11. For a square base w, the moving range of the clamp 11 is the range of half of the diagonal of the base w. During the polishing process, the base w moves horizontally while rotating, and the spray head 12 is fixed.

[0067] The cross section of the spray head 12 can be square or circular, and correspondingly, the area on which the spray head 12 sprays the polishing liquid on the base w is also square or circular. In embodiment one, the cross section of the spray head 12 is square, and when the base w rotates, the polishing liquid sprayed by the spray head 12 on the base w is uniform in the direction perpendicular to the linear velocity of the base w, so that the current is uniformly distributed.

[0068] The base w, the clamp 11, the polishing liquid, the spray head 12 and the power supply 13 form a polishing loop, and under the electrochemical action, the metal layer on the surface of the base w forms metal cations into the polishing liquid, thereby achieving the removal of the metal layer on the surface of the base w. The area of the base w directly contacted with the polishing liquid can remove the metal layer, and the removal rate of the corner area of the base w can be controlled by controlling the current size provided by the power supply 13 to the polishing loop or the residence time of the corner area of the base w above the spray head 12.

[0069] The device further comprises a control module for acquiring the current position of the base w during the horizontal movement, calculating and adjusting the current size of the base w at the current position and / or the horizontal movement speed of the base w according to the distance between the projection point of the center of the spray head 12 on the plane where the base w is located and the center of the base w.

[0070] The device further comprises an angle sensor for detecting the rotation angle of the base w. When the projection point of the center of the spray head 12 on the plane where the base w is located is located in the area between the inscribed circle and the circumscribed circle of the base w, the control module is further used for controlling the current to be turned on when the top corner of the base w rotates above the spray head 12, and controlling the current to be turned off when the top corner of the base w leaves above the spray head 12.

[0071] In the embodiment one, the substrate w moves at a constant speed in a horizontal direction during the polishing process. The current or the duty cycle of the current output is adjusted according to the distance between the projection point of the center of the showerhead 12 on the plane of the substrate w and the center of the substrate w, and the current is turned off when the corner region of the substrate w is out of the above of the showerhead 12, so as to control the removal rate of the corner region of the substrate w. Specifically, the distance r between the projection point of the center of the showerhead 12 on the plane of the substrate w and the center of the substrate w is obtained by the position of the horizontal movement of the substrate w, and the current I is controlled according to the following formula:

[0072] When 0≤r≤b, I=D*πb 2 ;

[0073] When b 2 <π(r-b) 2 ], when b 2 <π(r-b) 2 ], and when the top corner of the substrate w is out of the above of the showerhead 12, I=0.

[0074] When , and when the top corner of the substrate w is out of the above of the showerhead 12, I=0.

[0075] Wherein, as shown in FIG. 3, a is half of the side length of the substrate w, b is half of the side length of the area on which the polishing liquid is sprayed by the showerhead on the substrate w, and D is the current density.

[0076] Taking any one of the top corners of the substrate w as the reference top corner, taking the initial position of the reference top corner as 0°, and taking the angle difference between the reference top corner and the other three top corners as 90°, 180° and 270°. The angle sensor determines whether the top corner of the substrate w is above the showerhead 12 according to the angle of the reference top corner and the position of the showerhead 12. For example, four angle intervals can be preset, and the current is turned on when the reference top corner of the substrate w is in any angle interval, otherwise the current is turned off.

[0077] In the embodiment one, the corresponding current is calculated according to the total area of the area on which the polishing liquid is sprayed by the showerhead 12 on the substrate w when the substrate w rotates. When 0≤r≤b, the area on which the polishing liquid is sprayed by the showerhead 12 on the substrate w can always cover the circular area with a radius of r outward from the center of the substrate w as the substrate w rotates, and the current is calculated according to the area of the circular area. When b , only the corner region of the substrate w is above the showerhead 12 to receive the polishing liquid. In order to avoid the current gathering in the corner region, the current is controlled to be turned on only when the top corner of the substrate w is above the showerhead 12, otherwise the current is turned off, so as to control the removal rate of the surface of the substrate w and improve the polishing uniformity.

[0078] Example Two

[0079] The stress-free polishing apparatus of Example Two is the same as that of Example One, and will not be repeated here. The difference between Example Two and Example One is that the control method of the removal rate is different: during the polishing process, the current is constant, and the removal rate of the corner region of the substrate w is controlled by adjusting the horizontal moving speed of the substrate w, so as to ensure the uniformity of the polishing on the entire substrate w.

[0080] In Example Two, according to the distance between the projection point of the center of the showerhead 12 on the plane where the substrate w is located and the center of the substrate w, the horizontal moving speed of the substrate w is adjusted. When the projection point of the center of the showerhead 12 on the plane where the substrate w is located is located in the region between the inscribed circle and the circumscribed circle of the substrate w, the horizontal moving speed of the substrate w is increased, and the residence time of the corner region of the substrate w above the showerhead 12 is reduced, thereby controlling the removal rate of the corner region of the substrate w. Specifically, the distance r between the projection point of the center of the showerhead 12 on the plane where the substrate w is located and the center of the substrate w is obtained through the position of the horizontal movement of the substrate w, and the horizontal moving speed V of the substrate w is controlled according to the following formula:

[0081] When 0≤r≤b, V=V0;

[0082] When b

[0083] When ,

[0084] wherein V0 is a preset initial speed, a is half of the length of the side of the substrate w, and b is half of the length of the side of the region where the showerhead 12 sprays the polishing liquid on the substrate. As shown in FIG. 4, taking the center of the substrate w as the center of a circle and the distance between the projection point of the center of the showerhead 12 on the plane where the substrate w is located and the center of the substrate w as the radius, a circle C1 is formed, and the side of the substrate w intersects the circle C1. For each corner of the substrate w, the line connecting one of the intersection points and the center of the substrate w is L1, the line connecting the vertex of the corner and the center of the substrate w is L2, and the angle between L1 and L2 is θ. During the horizontal movement of the substrate w, θ can be obtained according to half of the length of the side of the substrate w a and the distance r between the projection point of the center of the showerhead 12 on the plane where the substrate w is located and the center of the substrate w.

[0085] In the second embodiment, when 0≤r≤b, the area on the substrate w sprayed by the spray head 12 covers a circular area with a radius of r as the substrate w rotates; when b r≤a, the area on the substrate w sprayed by the spray head 12 forms a ring, so the horizontal moving speed of the substrate w needs to be reduced and the residence time of the substrate w above the spray head 12 needs to be increased to ensure the uniformity of polishing; when

[0086] In the second embodiment, when r≤a, the horizontal moving speed of the substrate w can be increased and the rotation speed of the substrate w can be increased at the same time to reduce the residence time of the substrate w corner area above the spray head 12 and better control the removal rate of the corner area.

[0087] Embodiment three

[0088] The stress-free polishing device of the third embodiment is the same as that of the first embodiment, which will not be described again. The difference between the third embodiment and the first embodiment is that the control method of the removal rate is different: the removal rate of the corner area of the substrate w is controlled by simultaneously controlling the residence time of the corner area of the substrate w above the spray head 12 and the current. Specifically, according to the distance between the projection point of the center of the spray head 12 on the plane of the substrate w and the center of the substrate w, the current or the current output duty cycle is adjusted, and the horizontal moving speed of the substrate w is adjusted at the same time, so as to control the removal rate of the corner area of the substrate w. The combination of the two control methods in the foregoing embodiments can achieve better control effect of the removal rate and improve the polishing uniformity.

[0089] Embodiment four

[0090] Figure 5 discloses a structural schematic diagram of a stress-free polishing device of the fourth embodiment of the present application. The device is based on the principle of electrochemistry to electro-polish the substrate w. The device includes a clamp 21 for holding the substrate and an electrochemical polishing liquid spray head 22 arranged below the clamp 21. The spray head 22 is electrically connected to the negative electrode of a power supply 23, and the polishing liquid is sprayed from the spray head 22 and sprayed on the surface of the substrate w. The clamp 21 is a vacuum clamp for holding the substrate w by vacuum adsorption.

[0091] In the fourth embodiment, the structure of the spray head 22 can be the same as that of the spray head 12 in the first embodiment.

[0092] The top center of the clamp 21 is provided with a rotating shaft 25, which can rotate around its own center, thereby driving the clamp 21 to rotate. The device further comprises a crossbeam (not shown in the figure) arranged above the clamp 21, and the rotating shaft 25 is installed on the crossbeam, and the crossbeam can move horizontally, thereby driving the clamp 21 to move horizontally. During the polishing process, the substrate w moves horizontally while rotating.

[0093] As shown in FIGS. 5 and 6, the clamp 21 is in the shape of a circle concentric with the substrate w, and the diameter is greater than the length of the diagonal line of the substrate w. The area of the clamp 21 other than the area where the substrate w is placed is provided with a sacrificial ring 26, which is made of the same metal as the surface of the substrate w, and the sacrificial ring 26 is used to uniformly distribute the current when polishing the edge of the substrate w, so as to avoid the current from being concentrated in the four corner areas of the substrate w, thereby causing the removal rate to be too high and affecting the polishing uniformity.

[0094] The device further comprises an auxiliary nozzle 24 for spraying the polishing liquid to the outer edge of the sacrificial ring 26. The auxiliary nozzle 24 is fixedly connected with the crossbeam and is parallel to the substrate w, and can move horizontally together with the crossbeam. The auxiliary nozzle 24 is electrically connected with the positive electrode of the power supply 23, and the auxiliary nozzle 24, the substrate w, the sacrificial ring 26, the polishing liquid, the nozzle 22 and the power supply 23 form a polishing loop. Under the electrochemical action, the metal layer on the surface of the substrate w forms metal cations into the polishing liquid, thereby achieving the removal of the metal layer on the surface of the substrate w.

[0095] In order to avoid the situation that when the edge of the substrate w stays above the nozzle 22, the current directly connects from the nozzle 22 to the auxiliary nozzle 24, causing the surface of the substrate w to be short-circuited, it is necessary to ensure that the projections of the auxiliary nozzle 24 and the nozzle 22 on the substrate w do not overlap at all times when the substrate w moves horizontally. Specifically, during the horizontal movement of the substrate w, the projection points of the center of the nozzle 22 on the substrate w form a straight line, and the projection points of the center of the auxiliary nozzle 24 on the substrate w are outside this straight line, for example, as shown in FIG. 6, the line connecting the projection point of the center of the auxiliary nozzle 24 on the substrate w and the center of the substrate w is perpendicular to this straight line.

[0096] Due to the provision of the sacrificial ring 26, when controlling the removal rate, it is not necessary to separately control the staying time of the corner area of the substrate w above the nozzle 22 or the current size provided by the power supply 23 to the polishing loop, and the whole of the clamp 21 and the substrate w can be treated as a wafer.

[0097] The device further comprises a control module for obtaining the position of the horizontal movement of the substrate w, calculating and adjusting the current size of the substrate w at the current position and / or the horizontal movement speed of the substrate w according to the distance between the projection point of the center of the nozzle 22 on the plane where the substrate w is located and the center of the substrate w.

[0098] In embodiment four, the removal rate of the corner region of the substrate w is controlled by adjusting the current or the duty cycle of the current output according to the distance r between the projection point of the center of the showerhead 22 on the plane of the substrate w and the center of the substrate w. Specifically, the distance r between the projection point of the center of the showerhead 22 on the plane of the substrate w and the center of the substrate w is obtained by the position of the horizontal movement of the substrate w, and the current I is controlled according to the following formula:

[0099] When 0≤r≤b, I=D*πb 2 ;

[0100] When , I=D*[πr 2 -π(r-b) 2 ];

[0101] Wherein, as shown in FIG. 7, a is half of the side length of the substrate w, b is half of the side length of the area on which the polishing liquid is sprayed by the showerhead 22 on the substrate w, and D is the current density.

[0102] In embodiment four, the removal rate of the substrate w surface is controlled by calculating the corresponding current according to the total area of the region on which the polishing liquid is sprayed by the showerhead 22 on the substrate w when the substrate w rotates, so as to improve the polishing uniformity.

[0103] Embodiment five

[0104] The stress-free polishing device of embodiment five is the same as that of embodiment four, which will not be described again here. The difference between embodiment five and embodiment four is that the control method of the removal rate is different: the removal rate of the corner region of the substrate w is controlled by adjusting the horizontal movement speed of the substrate w.

[0105] In embodiment five, the removal rate of the corner region of the substrate w is controlled by adjusting the horizontal movement speed of the substrate w according to the distance r between the projection point of the center of the showerhead 22 on the plane of the substrate w and the center of the substrate w. Specifically, the distance r between the projection point of the center of the showerhead 22 on the plane of the substrate w and the center of the substrate w is obtained by the position of the horizontal movement of the substrate w, and the horizontal movement speed V of the substrate w is controlled according to the following formula:

[0106] When 0≤r≤b, V=V0;

[0107] When ,

[0108] Wherein, V0 is a preset initial speed, a is half of the side length of the substrate w, and b is half of the side length of the area on which the polishing liquid is sprayed by the showerhead 22 on the substrate w.

[0109] In embodiment five, when 0≤r≤b, the area on which the polishing liquid is sprayed by the showerhead 22 on the substrate w is always circular with the rotation of the substrate w, and the current is relatively concentrated; while When the substrate w rotates, the area on the substrate w where the polishing liquid is sprayed by the showerhead 22 forms a ring, so the horizontal moving speed of the substrate w needs to be reduced and the residence time of the substrate w above the showerhead 22 needs to be increased to ensure the uniformity of polishing.

[0110] Embodiment Six

[0111] The stress-free polishing device of embodiment six is the same as that of embodiment four, which will not be described again. The difference between embodiment six and embodiment four is that the control method of removal rate is different: the removal rate of the corner area of the substrate w is controlled by simultaneously controlling the residence time of the corner area of the substrate w above the showerhead 22 and the current size. Specifically, according to the distance between the projection point of the center of the showerhead 22 on the plane where the substrate w is located and the center of the substrate w, the current or current output duty cycle is adjusted, and at the same time, the horizontal moving speed of the substrate w is adjusted, so as to control the removal rate of the corner area of the substrate w. The combination of the two control methods in the foregoing embodiments can obtain better control effect of the removal rate and improve the polishing uniformity.

[0112] In the foregoing embodiments one to six, the showerhead can also be arranged to be linearly movable in the horizontal direction, and the clamp is arranged to only rotate, so that only the relative displacement of the showerhead and the substrate in the horizontal direction is needed, and correspondingly, the horizontal moving speed of the showerhead is adjusted, so as to control the removal rate of the corner area of the substrate.

[0113] The stress-free polishing device and the polishing method proposed in the foregoing embodiments can be applied to various planarization processes, such as substrate surface thinning and planarization in TGV (Through Glass Via) process, substrate surface thinning and planarization in double damascene process, correction of copper pillar height in copper pillar bump technology, and correction of RDL (Redistribution Layer) redistribution height in RDL local opening process.

[0114] The foregoing embodiments are only illustrative of the principles of the present application and its effects, and are not used to limit the present application. Any person skilled in the art can modify or change the foregoing embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed in the present application should be covered by the claims of the present application.

Claims

1. A stress-free polishing apparatus characterized by comprising: The utility model relates to a kind of polishing device, comprising: Clamp, for holding substrate and drive the rotation of the substrate, the clamp is equipped with conductive ring, the conductive ring is contacted with the edge of the substrate; Spray head, be arranged below the clamp, for the polishing liquid to the substrate spray, the spray head can be in horizontal direction with the substrate relative linear motion; Control module is configured to: obtain the distance between the projection point of the current center of the spray head on the plane where the substrate is located and substrate center, if the substrate is currently located above the spray head, then according to the distance adjustment current size and / or the relative moving speed of the spray head and the substrate.

2. The stress-free polishing apparatus according to claim 1, wherein The material of the clamp includes conductive metal.

3. The stress-free polishing apparatus of claim 1, wherein The shape of the cross section of the spray head is square.

4. The stress-free polishing apparatus of claim 1, wherein The clamp includes inner edge, and the inner edge is used to support the substrate, and the conductive ring is arranged on the inner edge.

5. The stress-free polishing apparatus of claim 4, wherein The inner edge of the clamp is also provided with sealing ring, and the sealing ring covers the conductive ring.

6. The stress-free polishing apparatus of claim 4, wherein It also includes a pressing plate, which is arranged between the clamp and the back of the substrate.

7. The stress-free polishing apparatus of claim 1, wherein It also includes an angle sensor for detecting the angle of substrate rotation; the control module is also configured to: when the projection point of the center of the spray head on the plane where the substrate is located is located in the area between the incircle and the circumscribed circle of the substrate, the control module controls the current to be turned on when the top angle of the substrate rotates above the spray head, and controls the current to be turned off when the top angle of the substrate leaves above the spray head.

8. The stress-free polishing apparatus of claim 7, wherein The control module is also configured to: control the spray head or the substrate to move at a constant speed in a straight line, and make the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate and the current size satisfy the following formula: I = D * πb when 0 < r < b 2 ; I = D * [πr 2 -π(r-b) 2 ] when b < r < a When I = D * [πr - π(r - b)] when the corner of the substrate is above the showerhead and the corner of the substrate is rotated above the showerhead, I = D * [πr - π(r - b)] 2 -π(r-b) 2 ]; when the corner of the substrate is not above the showerhead, I = 0; Wherein, r is the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate, a is half of the side length of the substrate, b is half of the side length of the area on the substrate where the spray head sprays polishing liquid, and D is the current density.

9. The stress-free polishing apparatus of claim 1, wherein The control module is configured to: keep the current size unchanged, and make the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate and the relative moving speed of the spray head and the substrate satisfy the following formula: When 0≤r≤b, V=V0. when b < r < a, When Time, Wherein, r is the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate, V0 is the preset initial speed, a is half of the side length of the substrate, b is half of the side length of the area on the substrate where the spray head sprays polishing liquid; the circle formed by the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate with the center of the substrate as the center and the radius intersects with the side of the substrate at multiple intersection points, and θ is the included angle between the line connecting one of the intersection points and the center of the substrate and the line connecting the adjacent vertex of the intersection point and the center of the substrate.

10. The stress-free polishing apparatus of claim 1, wherein The control module is configured to: control the substrate to remain stationary in the horizontal direction, and control the spray head to move linearly in the horizontal direction.

11. The stress-free polishing apparatus of claim 1, wherein The control module is configured to: control the position of the spray head to be fixed, and control the clamp to drive the substrate to move linearly in the horizontal direction.

12. A stress-free polishing apparatus characterized by comprising: ​ A clamp for holding a substrate, wherein a region other than a region for placing the substrate is provided with a sacrificial ring made of the same metal as the surface of the substrate, and the clamp is used to rotate the substrate and the sacrificial ring; A spray head is arranged below the clamp and used to spray polishing liquid to the substrate, and the spray head and the substrate can move linearly relative to each other in the horizontal direction; An auxiliary spray head is arranged below the clamp and is relatively static with the substrate in the horizontal direction, and is used to spray polishing liquid to the outer edge of the sacrificial ring.

13. The stress-free polishing apparatus of claim 12, wherein A control module is further included and configured to: acquire a distance between a projection point of a center of the spray head on a plane where the substrate is located and a center of the substrate, and adjust a current size and / or a relative moving speed of the spray head and the substrate according to the distance.

14. The stress-free polishing apparatus of claim 12, wherein The clamp is a vacuum clamp.

15. The stress-free polishing apparatus of claim 12, wherein The clamp is in the shape of a circle concentric with the substrate, and the diameter of the clamp is greater than the length of a diagonal line of the substrate.

16. The stress-free polishing apparatus of claim 12, wherein During horizontal movement of the clamp, the projections of the auxiliary spray head and the spray head on the substrate are always not coincident.

17. The stress-free polishing apparatus of claim 13, wherein The control module is further configured to: control the spray head or the substrate to move linearly at a uniform speed, and make the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate and the current size satisfy the following formula: I = D * πb when 0 < r < b 2 ; When At time t, I = D * [πr 2 - π(r - b) 2 ]; Wherein, a is half of the side length of the substrate, b is half of the side length of a region where the spray head sprays polishing liquid on the substrate, and D is the current density.

18. The stress-free polishing apparatus of claim 13, wherein The control module is further configured to: control the current size to be constant, and make the distance between the projection point of the center of the spray head on the plane where the substrate is located and the center of the substrate and the relative moving speed of the spray head and the substrate satisfy the following formula: When 0≤r≤b, V=V0. When Time, Wherein, V0 is a preset initial speed, a is half of the side length of the substrate, and b is half of the side length of a region where the spray head sprays polishing liquid on the substrate.

19. The stress-free polishing apparatus of claim 12, wherein The cross section of the spray head is in the shape of a square.

20. A stress-free polishing method applied to the stress-free polishing apparatus according to any one of claims 1 to 19, characterized by, The method comprises: Acquiring a distance between a projection point of a center of the spray head on a plane where the substrate is located and a center of the substrate; Adjusting a current size and / or a relative moving speed of the spray head and the substrate according to the distance.

21. The stress-free polishing method of claim 20, wherein The method further comprises: Detecting an angle of rotation of the substrate, and when the projection point of the center of the spray head on the plane where the substrate is located is located in a region between an inscribed circle and a circumscribed circle of the substrate and a top angle of the substrate rotates to above the spray head, controlling the current to be turned on, and when the top angle of the substrate leaves above the spray head, controlling the current to be turned off.

22. The stress-free polishing method of claim 20, wherein, The method is applied to a semiconductor process, and the semiconductor process comprises any one or more of a TGV process, a double-damascene process, a copper pillar bump technology and an RDL local opening process.

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