Device, method and equipment for adjusting local electroplating rate of wafer in electroplating process

Abstract

The invention provides a device and a method for adjusting the local electroplating rate of a wafer in an electroplating process and electroplating equipment. The device comprises an electroplating assembly and an electroplating rate adjusting assembly, the electroplating assembly comprises an electroplating head, an electroplating bath, anode metal and a power supply; the electroplating rate adjusting assembly comprises an auxiliary metal electrode and an on-off switch, the auxiliary metal electrode is arranged in a designated area and is completely or partially immersed in the electroplating liquid during electroplating, the auxiliary metal electrode is electrically connected with the negative electrode of the power supply, and the on-off switch is arranged on a connecting path where the auxiliary metal electrode is located; during electroplating, controlling the on-off of the on-off switch to adjust the electroplating rate of the periphery of the wafer gap in the period that the wafer gap rotates to be close to or slightly far away from the designated area where the auxiliary metal electrode is located. The electroplating rate adjusting assembly is arranged to adjust the electroplating rate of the periphery of the wafer notch in a targeted mode, the uniformity control problem of the current wafer electroplating process is solved, and the yield of wafers and the production economic benefits are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor electroplating processing, and specifically, to an apparatus for adjusting the local electroplating rate of a wafer in an electroplating process, a method for adjusting the local electroplating rate of a wafer using the apparatus, and an electroplating apparatus including the apparatus. Background Art

[0002] The metal electroplating process is widely used in application fields such as integrated circuits and board-level interconnections. Currently, electroplating processes are commonly used in fields such as the damascene metal interconnect of integrated circuit chips, advanced packaging such as 2.5D / 3D integration, and fan-in / fan-out packaging to process metal wires and metal contacts.

[0003] Currently, the electroplating process applied to the integrated circuit semiconductor manufacturing process is mainly wafer-level planar electroplating, that is, depositing metal on the surface of a circular wafer or a selected area on the wafer surface through an electroplating apparatus and an electroplating process. The electroplating apparatus mainly includes an electroplating tank, an electroplating head, and other mechanical transmission devices. The electroplating tank is used to hold the plating solution and other chemical agents, and the electroplating head is used to load the wafer. During the electroplating process, the electroplating head clamps the wafer, immerses the surface of the wafer to be electroplated into the electroplating solution in the electroplating tank, and through a metal anode electrode placed in the electroplating tank and a metal cathode electrode installed on the electroplating head, an electric current path for an electrochemical reaction is formed between the wafer to be electroplated and the electroplating solution. The current of the metal anode electrode will be evenly distributed in the electroplating solution in the electroplating tank, and the metal cathode electrode will form an electrical conduction path through the metal contacts on the electroplating head and the conductive layer on the wafer. An electroplating reaction will occur on the surface of the electroplating solution and the wafer to be electroplated, continuously reducing metal ions from the plating solution and depositing them on the surface of the wafer to be electroplated.

[0004] During the electroplating process, it is necessary to control the current distribution on the entire wafer to adjust the electroplating rate of each area on the wafer surface, that is, to adjust the thickness of metal deposition in each area. Generally, in order to obtain better uniformity, the metal anode electrode will be divided into different areas for separate control, and according to the different areas covered, the current density of each metal anode electrode is correspondingly adjusted to achieve as uniform a distribution as possible in the entire electroplating tank. Figure 1 Fig. shows an anode electrode adopted in the prior art, which includes a first electrode 3 located at the center and a circular second electrode 4 surrounding the first electrode 3. The first electrode 3 is located in the central area of the electroplating cavity, and the second electrode 4 is located at the peripheral position in the electroplating cavity. The circular first electrode 3 and the circular second electrode 4 both have a symmetric structure, so the electric field generated by them is also symmetric and uniform. In an ideal state, when the wafer to be electroplated is a complete regular circle, the complete regular circular wafer is as shown in Figure 1Electroplating is carried out under the uniform and symmetric electric field formed by the anode electrode shown, and an ideal and uniform electroplated layer should be able to be obtained. During this process, rotating the wafer held by the electroplating head in the electroplating solution can further increase the current distribution and the uniformity of electroplating.

[0005] However, although the prior art has improved the uniformity of current distribution by taking measures such as segmented anodes and wafer rotation during electroplating as described above, unfortunately, the wafer itself is often not a perfect circle. For example, Figure 2 as shown, there is usually a small notch 5 on a large-sized wafer to help position the direction of the wafer, and Figure 3 as shown, a flat edge 6 of a certain length is used on a small-sized wafer to achieve the same function. The flat edge 6 and the notch 5 form non-electroplating areas of the wafer. When electroplating the wafer, in a uniform electric field environment, since there are no wires in the non-electroplating areas, no current can be generated, which will cause a larger current to be generated in the wires located around them. As a result, the positions around the non-electroplating areas are actually under a larger current density, resulting in a higher electroplating thickness around the flat edge 6 and the notch 5 than in other areas, causing non-uniformity of electroplating and reducing the reliability of semiconductor devices. In addition, in some requirements, the chip die on the wafer is unevenly distributed, which will generate non-electroplating areas with irregular shapes. The areas on the wafer where chips are arranged have many openings of photoresist, and these openings can play a conductive role, and metal will be deposited during electroplating; while the areas without chips do not have photoresist openings and cannot conduct electricity, resulting in no metal deposition. These two differences cause the conductive current intensity and electroplating rate to be different in the two different areas, ultimately resulting in non-uniform electroplating layer thickness in different areas and a very high point or area in thickness on the wafer surface, and the reliability of semiconductor devices is poor.

[0006] In view of the negative impact of non-electroplating areas such as the flat edge 6 and the notch 5 of the wafer (for the convenience of description, this patent collectively refers to such non-electroplating areas as notches) on the electroplating effect, if it is not properly solved, the electroplating effect of the wafer with notches will be greatly limited. Summary of the Invention

[0007] Aiming at the defects in the prior art, the purpose of the present invention is to provide a device, a method and an electroplating equipment for adjusting the local electroplating rate of a wafer in an electroplating process. By setting an electroplating rate adjustment component to specifically adjust the electroplating rate of the area near the notch of the wafer, the problem of uniformity control in the wafer electroplating process in current semiconductor manufacturing is solved, which is beneficial to improving the yield of the wafer and the economic benefits of production.

[0008] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0009] According to the first aspect of the present invention, there is provided a device for adjusting the local electroplating rate of a wafer in an electroplating process, including an electroplating assembly and an electroplating rate adjusting assembly;

[0010] The electroplating assembly includes an electroplating head, an electroplating tank, an anode metal, and a power supply; the electroplating head is used to hold the wafer and can drive the wafer to rotate; the anode metal is arranged in the electroplating tank and is immersed in the electroplating solution during electroplating; the positive electrode of the power supply is electrically connected to the anode metal, and the negative electrode of the power supply is electrically connected to the electroplating head;

[0011] The electroplating rate adjusting assembly includes an auxiliary metal electrode and a switching device. The auxiliary metal electrode is arranged in a designated area in the electroplating tank and is completely or partially immersed in the electroplating solution during electroplating. The auxiliary metal electrode is electrically connected to the negative electrode of the power supply, and the switching device is arranged on the connection path where the auxiliary metal electrode is located;

[0012] During the electroplating process, the wafer rotates driven by the electroplating head. During the period when the notch of the wafer rotates to be about to approach and slightly move away from the designated area where the auxiliary metal electrode is located, the opening and closing of the switching device are controlled to adjust the electroplating rate around the notch of the wafer.

[0013] In this technical solution, by setting the electroplating rate adjusting assembly, when the switching device on the connection path where the auxiliary metal electrode is located is in the closed state, the auxiliary metal electrode and the cathode metal electrode are in an electrically conductive state. As a result, an additional loop of anode metal electrode, electroplating solution, auxiliary metal electrode, and the negative electrode of the power supply is added to the current loop between the anode metal electrode, electroplating solution, wafer surface, and cathode metal electrode. By shunting the current on the wafer surface, the effect of controlling the current distribution on the wafer surface is achieved, forming the adjustment of the local electroplating rate of the wafer in the electroplating process, thereby solving the control problem of adjusting the local electroplating rate of the wafer in the current electroplating process, which is beneficial to improving the yield of the wafer and the economic benefits of production. It should be noted that the so-called "notch" in this technical solution is a general term for non-electroplating areas such as wafer notches and flat edges.

[0014] Preferably, during the electroplating process, the position of the wafer in the electroplating tank is defined as the wafer electroplating position; the auxiliary metal electrode is arranged on the side wall of the electroplating tank, and the height of the auxiliary metal electrode is flush with the wafer electroplating position or the auxiliary metal electrode is located in height between the wafer electroplating position and the anode metal.

[0015] In this technical solution, when the auxiliary metal electrode is arranged on the side wall of the electroplating tank and designed close to the wafer electroplating position, its influence range can be more concentrated on the notch at the periphery of the wafer, thereby improving the adjustment of the electroplating rate around the notch.

[0016] Preferably, the electroplating rate adjusting assembly further includes a resistor assembly, and the resistor assembly is connected in series with the auxiliary metal electrode.

[0017] In this technical solution, the current flowing through the auxiliary metal electrode can be adjusted by a resistance component connected in series with the auxiliary metal electrode, so as to better meet the needs of users.

[0018] Preferably, the resistance component includes one or more resistance units, and each resistance unit includes one or more resistors. When the resistance unit includes multiple resistors, the multiple resistors are connected in series and / or in parallel.

[0019] In this technical solution, when the resistance component includes multiple resistance units, the user can select any one or more resistance units to be connected in different electroplating stages according to actual needs. When the connected resistance unit includes multiple resistors, the user can further select one or more resistors of the resistance unit on this basis, so as to obtain different current magnitudes in different electroplating stages, and then generate different adjustments to the electroplating rate of the area around the wafer notch.

[0020] Preferably, the electroplating rate adjustment component further includes a control module, and the control module is used to control any one or more of the following parameters of the connection path where the auxiliary metal electrode is located: the closing time of the on-off switch, the power-on interval, the pulsation frequency, the duty ratio, and the resistance value of the resistance component.

[0021] In this technical solution, through software setting of the control module, when the wafer notch approaches the auxiliary metal electrode, passes by the auxiliary metal electrode, and moves away from the metal electrode during rotation, the above parameters of the connection path where the auxiliary metal electrode is located can be controlled according to actual needs, so as to specifically improve the uniformity of the wafer electroplating layer. Among them, the so-called control of the resistance value of the resistance component is mainly to select different resistor combinations of the resistance component (at this time the resistance component includes multiple resistors) according to the current required by different process steps.

[0022] Preferably, the shape of the immersed part of the auxiliary metal electrode in the electroplating solution is columnar or fan-shaped; the material of the auxiliary metal electrode is copper, or a specified metal adapted to the composition of the electroplating solution or copper covered with a specified metal.

[0023] In this technical solution, when the auxiliary metal electrode is completely immersed in the electroplating solution, its overall shape is columnar or fan-shaped. When only partially immersed in the electroplating solution, the shape of its immersed part is columnar or fan-shaped; generally, the main material of the auxiliary metal electrode is copper, but the user can also replace it with other metals or copper covered with other metals according to the composition of the electroplating solution.

[0024] Preferably, the number of the electroplating rate adjustment components is one or more. When the number of the electroplating rate adjustment components is multiple, the auxiliary metal electrodes included in the multiple electroplating rate adjustment components are evenly arranged in the electroplating tank.

[0025] In this technical solution, the user can choose to set multiple electroplating rate adjustment components to control the electroplating film formation rate near the notch, so that the electroplated layer near the notch is consistent with other parts of the wafer, optimizing the uniformity of the electroplated layer. Regarding the number of electroplating rate adjustment components, it can be set according to the arc length ratio of the actual notch (for example, flat edge or notch arc length * 1 / 3 = number of electroplating rate regulators).

[0026] According to the second aspect of the present invention, there is provided a method for adjusting the local electroplating rate of a wafer in an electroplating process. Using the device for adjusting the local electroplating rate of a wafer in the electroplating process described in any one of the above, the method includes the following steps:

[0027] S10. Define that during the electroplating process, the position of the wafer in the electroplating tank is the wafer electroplating position. Use the electroplating head to hold the wafer to reach the wafer electroplating position, and control the electroplating head to drive the wafer to rotate at the wafer electroplating position;

[0028] S20. During each rotation cycle of the wafer, close the opening and closing switch during the period when the wafer notch is about to approach and slightly move away from the designated area where the auxiliary metal electrode is located, so as to adjust the electroplating rate around the wafer notch; or after several wafer rotation cycles, close the opening and closing switch during a certain rotation cycle when the wafer notch is about to approach and slightly move away from the designated area where the auxiliary metal electrode is located, so as to intermittently adjust the electroplating rate around the wafer notch.

[0029] In this technical solution, by setting the electroplating rate adjustment component, when the notch of the wafer approaches the auxiliary metal electrode, the opening and closing switch on the connection path where the auxiliary metal electrode is located is in a closed state, and the auxiliary metal electrode and the cathode metal electrode are in an electrically conductive state. As a result, an additional loop of anode metal electrode, electroplating solution, auxiliary metal electrode and power supply negative pole is added to the current loop between the anode metal electrode, electroplating solution, wafer surface and cathode metal electrode. By shunting the current on the wafer surface, the effect of controlling the current distribution on the wafer surface is achieved, forming the adjustment of the local electroplating rate of the wafer in the electroplating process. It should be noted that in this technical solution, the so-called "or after several wafer rotation cycles" does not require the number of intervals to be uniform, that is, the opening and closing switch can be controlled after intervals of different numbers of rotation cycles to be able to adaptively adjust the electroplating rate around the wafer notch according to actual needs.

[0030] Preferably, when the auxiliary metal electrode is connected in series with the resistance component and the resistance component includes multiple resistors, step S20 further includes: selecting the resistance combination of the resistance component to adjust the electroplating rate around the wafer notch.

[0031] In this technical solution, the current flowing through the auxiliary metal electrode can be adjusted by a resistance component connected in series with the auxiliary metal electrode. And after the opening and closing switch in the connection path where the auxiliary metal electrode is located is closed each time, the resistance value of the resistance component can be independently adjusted according to actual needs (the adjustment method is mainly achieved by selecting different resistance combinations included in the resistance component), so as to obtain different current magnitudes at different stages of electroplating, and further generate different adjustments to the electroplating rate of the wafer notch or flat edge area.

[0032] Preferably, when the electroplating rate adjustment component further includes a control module, step S20 further includes: controlling any one or more of the following parameters of the connection path where the auxiliary metal electrode is located through the control module: the closing time of the opening and closing switch, the power-on interval, the pulsation frequency, the duty cycle, and the resistance value of the resistance component.

[0033] In this technical solution, through the software setting of the control module, when the notch of the wafer approaches the auxiliary metal electrode, passes through the auxiliary metal electrode, and moves away from the metal electrode during rotation, the above parameters of the connection path where the auxiliary metal electrode is located can be controlled according to actual needs, so as to specifically improve the uniformity of the electroplating layer of the wafer. Among them, the so-called control of the resistance value of the resistance component is mainly to select different resistance combinations of the resistance component (at this time, the resistance component includes multiple resistors) according to the current required by different process steps.

[0034] According to the third aspect of the present invention, there is provided an electroplating apparatus including the device for adjusting the local electroplating rate of the wafer in any one of the above electroplating processes.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. By setting the electroplating rate adjustment component to specifically adjust the electroplating rate of the area near the wafer notch, the present invention solves the problem of the uniformity control in the current wafer electroplating process, which is beneficial to improving the yield of the wafer and the economic benefits of production.

[0037] 2. The influence range and influence degree of the electroplating rate adjustment component of the present invention can be flexibly adjusted by selecting the closing time of the opening and closing switch and dynamically adjusting the resistance value of the further provided series-connected resistance component. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] By reading the detailed description of the non-restrictive embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more apparent:

[0039] Figure 1 It is a schematic structural diagram of a partitioned anode electrode adopted in the prior art;

[0040] Figure 2 Schematic structural diagram of a wafer with a notch design;

[0041] Figure 3 Schematic structural diagram of a wafer with a flat edge design;

[0042] Figure 4 Schematic structural diagram of the device for adjusting the local electroplating rate according to the first embodiment of the present invention;

[0043] Figure 5 Partial structural diagram of the device for adjusting the local electroplating rate according to the first embodiment of the present invention;

[0044] Figure 6 Schematic diagram of the rotation of the wafer notch relative to the auxiliary metal electrode in the first embodiment of the present invention;

[0045] Figure 7 Principle concept diagram of the device for adjusting the local electroplating rate according to the first embodiment of the present invention;

[0046] Figure 8 First design schematic diagram of the resistor component according to the second embodiment of the present invention;

[0047] Figure 9 Second design schematic diagram of the resistor component according to the second embodiment of the present invention;

[0048] Figure 10 Third design schematic diagram of the resistor component according to the second embodiment of the present invention;

[0049] Figure 11 Schematic diagram of the distribution of the auxiliary metal electrodes of the device for adjusting the local electroplating rate according to the third embodiment of the present invention;

[0050] Figure 12 Schematic diagram of the distribution of the auxiliary metal electrodes of the device for adjusting the local electroplating rate according to other embodiments of the present invention;

[0051] Figure 13 Flow chart of the method for adjusting the local electroplating rate according to the fifth embodiment of the present invention.

[0052] As shown in the figure:

[0053] 1 - Electroplating assembly

[0054] 101 - Electroplating head

[0055] 102 - Electroplating tank

[0056] 103 - Anode metal

[0057] 104 - Power supply

[0058] 105 - Wafer

[0059] 2 - Electroplating Rate Adjustment Component

[0060] 201 - Auxiliary Metal Electrode

[0061] 202 - Opening and Closing Switch;

[0062] 7 - Connection Point;

[0063] 8 - Resistance Component;

[0064] 3 - First Electrode

[0065] 4 - Second Electrode

[0066] 5 - Notch

[0067] 6 - Flat Edge Detailed Implementation Manner

[0068] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. Usually, the components of the embodiments of this application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0069] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0070] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, all directional indications (such as up, down, left, right, front, back, bottom...) in this application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If this specific posture changes, then the directional indications will also change accordingly. Further, the descriptions involving "first", "second", etc. in the application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features.

[0071] Embodiment 1

[0072] As Figure 4 and Figure 5As shown, this embodiment provides a device for adjusting the local electroplating rate of a wafer in an electroplating process, which is used for electroplating on the surface of a wafer with a notch. The device generally includes an electroplating component 1 and an electroplating rate adjustment component 2. Among them, the electroplating rate adjustment component 2 is used to adjust the electroplating rate of the area around the wafer notch.

[0073] Specifically, the electroplating component 1 includes an electroplating head 101, an electroplating tank 102, an anode metal 103, and a power supply 104. Among them, the electroplating head 101 is used to hold the wafer 105 and can drive the wafer 105 to rotate. The electroplating tank 102 is used to hold the electroplating solution. The anode metal 103 is arranged in the electroplating tank 102 and is immersed in the electroplating solution during electroplating. The positive electrode of the power supply 104 is electrically connected to the anode metal 103, and the negative electrode of the power supply 104 is electrically connected to the electroplating head 101. After the power supply 104 is turned on, an electric current path for an electrochemical reaction is formed between the wafer 105 to be electroplated and the electroplating solution, and metal ions in the electroplating solution are continuously reduced and deposited on the surface of the wafer 105 to be electroplated.

[0074] The electroplating rate adjustment component 2 includes an auxiliary metal electrode 201 and a switching switch 202. Among them, the auxiliary metal electrode 201 is arranged in a designated area in the electroplating tank 102 and is fully or partially immersed in the electroplating solution during electroplating. The auxiliary metal electrode 201 is electrically connected to the negative electrode of the power supply 104. The switching switch 202 is arranged on the connection path where the auxiliary metal electrode 201 is located. During the electroplating process, the wafer 105 rotates driven by the electroplating head 101. During the period when the notch of the wafer 105 rotates from about to approach to slightly away from the designated area where the auxiliary metal electrode 201 is located, the switching switch 202 can be closed to adjust the electroplating rate around the notch of the wafer 105.

[0075] As Figure 6 shown, in this embodiment, the notch of the wafer 105 is located at the circumferential boundary position of the wafer 105. To enable the electroplating rate adjustment component 2 to better play its adjustment role, the auxiliary metal electrode 201 is arranged on the inner side wall of the electroplating tank 102, and in terms of height, the auxiliary metal electrode 201 is arranged close to the wafer electroplating position (defining the position of the wafer 105 in the electroplating tank 102 during the electroplating process as the wafer electroplating position). It can be at the same height as the wafer electroplating position or at a certain position between the anode metal 103 and the wafer electroplating position.

[0076] During the electroplating process, the electroplating tank 102 holds the electroplating solution. The electroplating head 101 holds the wafer 105 and makes it reach the wafer electroplating position. At the same time, the electroplating head 101 drives the wafer 105 to rotate at the wafer electroplating position to improve the uniformity of electroplating. As Figure 6As shown, during the rotation of the wafer 105, the position of the auxiliary metal electrode 201 remains fixed. With respect to the position of the auxiliary metal electrode 201, the notch of the wafer 105 goes through four stages: approaching the auxiliary metal electrode 201, passing by the auxiliary metal electrode 201, slightly moving away from the auxiliary metal electrode 201, and moving away from the auxiliary metal electrode 201. During the period when the notch of the wafer 105 is approaching the auxiliary metal electrode 201 to slightly moving away from it, control can be exerted on the opening and closing switch 202. For example, one or more closing times can be set for the opening and closing switch 202. When the opening and closing switch 202 is in the closed state, the auxiliary metal electrode 201 and the cathode metal electrode are in an electrically conductive state, thus forming two circuits within the device. One is the first circuit formed between the anode metal 103 electrode, the plating solution, the surface of the wafer 105, and the cathode metal electrode. The other is the second circuit formed between the anode metal 103 electrode, the plating solution, the auxiliary metal electrode 201, and the negative pole of the power supply 104. By diverting the current provided for the periphery of the notch of the wafer 105 from the first circuit, the current distribution on the surface of the wafer 105 is controlled, thereby adjusting the plating rate of the periphery of the notch of the wafer 105.

[0077] It should be noted that the realization of the technical effect of this device does not require the opening and closing switch 202 to be closed during each rotation of the wafer 105. The user can set to close the opening and closing switch 202 within a certain rotation cycle after several rotation cycles according to actual needs, so as to intermittently adjust the plating rate of the periphery of the notch of the wafer 105.

[0078] Furthermore, the plating rate adjustment component 2 further includes a resistor component 8, and the resistor component 8 is connected in series on the path where the auxiliary metal electrode 201 is located. After the opening and closing switch 202 on the circuit where the auxiliary metal electrode 201 is located is closed, the current flowing to the cathode metal electrode can be adjusted in real time through the resistor component 8. At the same time, the resistance value of the resistor component 8 during each closing can also be independently adjusted to obtain different current magnitudes, thereby generating different adjustments to the plating rate of the periphery of the notch of the wafer 105. Among them, the so-called adjustment of the resistance value of the resistor component 8 mainly involves selecting different resistor combinations of the resistor component 8 (at this time, the resistor component 8 includes multiple resistors) according to the current required by different process steps.

[0079] In addition, the electroplating rate adjustment component 2 further includes a control module, which is used to control one or more parameters of the connection path where the auxiliary metal electrode 201 is located during the electroplating process, including the closing time of the on-off switch 202, the power-on interval, the pulsation frequency, the duty cycle, the resistance value of the resistance component 8, etc., so as to precisely adjust the electroplating rate for a certain period of time around the notch of the wafer 105. The specific usage method can be to set the control module so that the closing time of the on-off switch 202 of the connection path where the auxiliary metal electrode 201 is located can be controlled in three stages when the notch of the wafer 105 approaches, passes by, and slightly moves away from the auxiliary metal electrode 201 during rotation. Furthermore, it can also be set to perform the same closing operation every time it rotates past, or perform the same closing operation after several rotations, or perform different closing operations at different rotation numbers. Furthermore, the total current flowing through the auxiliary metal electrode 201 during each closing can be controlled by the series-connected resistance component 8.

[0080] Regarding the design of the auxiliary metal electrode 201, its overall shape is columnar or fan-shaped, or when only part of the auxiliary metal electrode 201 is immersed in the electroplating solution, the shape of the immersed part of the auxiliary metal electrode 201 is columnar or fan-shaped. Generally, the main material of the auxiliary metal electrode 201 is copper. Of course, the user can also replace it with other metals according to the composition of the electroplating solution, or choose a material with copper as the main material but with other metals covering the copper surface. Regarding the on-off switch 202 of the path where the auxiliary metal electrode 201 is located, it can be a solid-state relay, and the on-off of the electrical path between the auxiliary metal electrode 201 and the negative pole of the power supply 104 is controlled by the opening and closing of the solid-state relay.

[0081] In the electroplating process provided by this embodiment, a device for adjusting the local electroplating rate of a wafer is provided. By setting an auxiliary metal electrode 201 in a specified area in an electroplating bath 102 at a certain distance from a rotating electroplating head 101, the height of the auxiliary metal electrode 201 and the electroplating head 101 when the wafer 105 is immersed in the electroplating bath 102 and starts to rotate is at the same horizontal plane, or the auxiliary metal electrode 201 is located at a certain position between this horizontal plane and the metal anode electrode 103. The auxiliary metal electrode 201 is completely or partially immersed in the electroplating solution. The auxiliary metal electrode 201 is directly connected to the cathode potential of the electroplating head 101 or connected to the cathode potential of the electroplating head 101 in series with a resistance component 8, and an opening and closing switch 202 is provided in the path. Obviously, by installing the device proposed in this application, a loop between the anode metal electrode, the electroplating solution, the auxiliary metal electrode and the negative pole of the power supply can be added to the current loop between the anode metal electrode, the electroplating solution, the wafer surface and the cathode metal electrode. By shunting the current on the wafer surface, the effect of controlling the current distribution on the wafer surface is achieved, and the adjustment of the local electroplating rate of the wafer in the electroplating process is formed.

[0082] Regarding the reason for limiting the connection of the auxiliary metal electrode 201 to the negative pole of the power supply 104 in this embodiment, as Figure 7 shown, theoretically, the current flowing out of the positive pole of the power supply 104 should be equal to the current flowing into the negative pole of the power supply. When the auxiliary metal electrode 201 (when the auxiliary metal electrode 201 is connected in series with a resistance component 8, the series resistance component 8 is also included here) is directly overlapped Figure 7 by a dotted line to the cathode wafer metal electrode, the potential at the connection point 7 is the same as when there is no auxiliary metal electrode 201. That is, assuming that the power supply positive pole outputs 1 ampere of current, the current from the connection point 7 to the negative pole of the power supply is still 1 ampere. This 1 ampere of current multiplied by the resistance value is the voltage from the "cathode metal electrode" to the "negative pole of the power supply". That is to say, regardless of whether there is an auxiliary metal electrode 201 in this connection, the potential of the wafer metal electrode (conductive ring cathode) remains unchanged, that is, the current from this point to the negative pole of the power supply remains unchanged, so there is no adjustment effect. If the auxiliary metal electrode 201 (when the auxiliary metal electrode 201 is connected in series with a resistance component 8, the series resistance component 8 is also included here) is connected to the negative pole of the power supply (that is, the dotted line is disconnected), then the potential of the wafer metal electrode is not 1 ampere multiplied by the resistance value from the cathode metal electrode to the negative pole of the power supply. In this way, the current from the wafer metal electrode to the negative pole of the power supply changes, and the adjustment effect is achieved.

[0083] Embodiment 2

[0084] Based on the solution of Embodiment 1, this embodiment further designs the resistor component 8. In this embodiment, the resistor component 8 includes one or more resistor units, and each resistor unit includes one or more resistors; when a resistor unit includes multiple resistors, the multiple resistors are connected in series and / or in parallel. The user can, according to the electroplating requirements, connect one or more resistor units to the connection path where the auxiliary metal electrode is located, and on this basis, connect one or more resistors of this resistor unit.

[0085] The following will Figures 8 to 10 give examples of the design of the resistor component 8 to better illustrate how to dynamically adjust the influence range and influence degree of the electroplating rate adjustment component 2 through the design of the resistor component 8. Specifically:

[0086] Figure 8 The first example is shown, in which the resistor component 8 includes only one resistor unit, this resistor unit includes only one resistor, this resistor is connected in series with the auxiliary metal electrode, and this resistor is an adjustable resistor that can be adjusted within a certain range.

[0087] Figure 9 The second example is shown, in which the resistor component 8 includes two resistor units, one resistor unit includes resistor R1, and the other resistor unit includes resistor R2. The connection relationship between resistor R1 and R2 and the auxiliary metal electrode is as Figure 9 shown. On the premise that the opening and closing switch 202 is in the closed state, when:

[0088] ① Both switch a and switch b are off, then resistor R1 is connected;

[0089] ② Switch a is closed and switch b is off, then the parallel-connected resistor R1 and resistor R2 are connected;

[0090] ③ Switch a (whether open or closed), switch b is closed. At this time, the line resistance where switch b is located is zero, so the current basically passes through here.

[0091] The user can select the off and on states of switches a and b, and the length of time for switches a and b to be off and on according to actual needs, thereby dynamically adjusting the current provided to the periphery of the notch of the wafer 105, so as to achieve the effect of controlling the current distribution on the surface of the wafer 105.

[0092] Figure 10 The third example is shown, in which the resistor component 8 as a whole includes two resistor units. One resistor unit includes resistors R1, R2, and R3, and the other resistor unit includes resistors R1', R2', and R3'. The connection relationship between R1, R2, R3, R1', R2', and R3' and the auxiliary metal electrode is as Figure 10 shown.

[0093] ①When the main switch K 总 is at point e, the circuit is open;

[0094] ②When the main switch K 总 is at point d: When the resistance switch is closed to point a, the resistor R1 is connected. When the resistance switch is closed to point b, the parallel resistors R2 and R3 are connected. When the resistance switch is closed to point c between a and b, no resistor is connected;

[0095] ③When the main switch K 总 is at point f: When the resistance switch is closed to point a', the resistor R1' is connected. When the resistance switch is closed to point b', the parallel resistors R2' and R3' are connected. When the resistance switch is closed to point c' between a' and b', no resistor is connected.

[0096] The user can select the open and closed states of each switch and the opening and closing times according to actual needs, thereby dynamically adjusting the current provided around the notch of the wafer 105, so as to achieve the effect of controlling the current distribution on the surface of the wafer 105.

[0097] Embodiment 3

[0098] This embodiment provides a device for adjusting the local electroplating rate of a wafer in an electroplating process. The structure of this device is generally the same as that of the device provided in Embodiment 1, except that: The device provided in this embodiment includes 3 electroplating rate adjustment components 2, as Figure 11 shown. The 3 auxiliary metal electrodes 201 included in these 3 electroplating rate adjustment components 2 are evenly distributed on the inner side wall of the electroplating tank 102.

[0099] During the electroplating process, when the wafer 105 is in a rotating state, the notch of the wafer 105 and each auxiliary metal electrode 201 all present four stages: about to approach the auxiliary metal electrode 201, passing by the auxiliary metal electrode 201, slightly away from the auxiliary metal electrode 201, and away from the auxiliary metal electrode 201. During the period from when the notch of the wafer 105 is about to approach a certain auxiliary metal electrode 201 to slightly away from the auxiliary metal electrode 201, the opening and closing switch 202 can be controlled by the control module to set one or more closing times for the opening and closing switch 202. When the opening and closing switch 202 is in the closed state, the auxiliary metal electrode 201 and the cathode metal electrode are in an electrically conductive state, thereby adjusting the electroplating rate around the notch of the wafer 105.

[0100] It should be emphasized that although three auxiliary metal electrodes are provided in this embodiment, it is not required that the opening and closing switches 202 on the connection paths where the three auxiliary metal electrodes 201 are located be in a sequentially closed state within a certain rotation cycle of the wafer. The user can choose when to close the opening and closing switches 202 on the connection paths where the auxiliary metal electrodes 201 are located, which auxiliary metal electrode 201's connection path's opening and closing switch 202 to close, how many auxiliary metal electrodes 201's connection path's opening and closing switches 202 to close, and the interval time for closing the opening and closing switches 202 on the connection paths where the auxiliary metal electrodes 201 are located according to actual needs.

[0101] In addition, in other embodiments, the number of the electroplating rate adjustment components 2 can be set according to the arc length ratio of the notch on the wafer 105. For example, the number of the electroplating rate adjustment components 2 can be configured to be equal to the notch arc length * 1 / 3. In another embodiment, the device includes six electroplating rate adjustment components 2, and as Figure 12 shown, the six auxiliary metal electrodes 201 included in the six electroplating rate adjustment components 2 are evenly distributed on the inner side wall of the electroplating tank 102. Controlling the current distribution by configuring a plurality of evenly distributed auxiliary metal electrodes 201 to control the electroplating film formation rate near the notch helps to reduce the problem of uneven current density caused by the existence of the notch during the wafer electroplating process, making the electroplated layer near the notch consistent with other parts of the wafer.

[0102] Embodiment 4

[0103] This embodiment provides an electroplating device, including the device for adjusting the local electroplating rate of the wafer in the electroplating process described in any of the above embodiments.

[0104] Embodiment 5

[0105] As Figure 13 shown, this embodiment provides a method for adjusting the local electroplating rate of the wafer in the electroplating process. Using the device for adjusting the local electroplating rate of the wafer in the electroplating process described in any of the above, the method includes the following steps:

[0106] S10. Use the electroplating head 101 to clamp the wafer 105 to the wafer electroplating position in the electroplating tank 102. At the same time, the electroplating head 101 drives the wafer 105 to rotate at the wafer electroplating position to improve the electroplating uniformity;

[0107] S20. During the period when the notch of the wafer 105 is about to approach and is slightly away from the auxiliary metal electrode 201, the opening and closing switch 202 is controlled by the control module. When the opening and closing switch 202 is in the closed state, electrical conduction is established between the auxiliary metal electrode 201 and the cathode metal electrode, thereby forming two loops in the device. One is the first loop formed between the anode metal 103 electrode, the electroplating solution, the surface of the wafer 105, and the cathode metal electrode. The other is the second loop formed between the anode metal 103 electrode, the electroplating solution, the auxiliary metal electrode 201, and the negative electrode of the power supply 104. The second loop controls the current distribution on the surface of the wafer 105 by diverting the current provided by the first loop to the area around the notch of the wafer 105, thereby adjusting the electroplating rate of the area around the notch of the wafer 105.

[0108] This embodiment proposes a method for adjusting the local electroplating rate of a wafer in an electroplating process. During the electroplating process, by setting any one or more parameters such as the closing time, power-on interval, pulsation frequency, duty cycle, and resistance value of the resistance component of the connection path where the auxiliary metal electrode 201 is located, the electroplating rate of a certain area of the wafer can be accurately adjusted for a certain period of time. The specific usage method can be that through the software setting of the control module, when the notch of the wafer 105 approaches the auxiliary metal electrode 201, passes by the auxiliary metal electrode 201, and is slightly away from the auxiliary metal electrode 201 during rotation, the closing time of the opening and closing switch 202 of the connection path where the auxiliary metal electrode 201 is located is controlled. Further, it can also be set that the same opening and closing switch 202 closing operation is performed each time the notch of the wafer 105 rotates past the auxiliary metal electrode 201, or the same opening and closing switch 202 closing operation is performed after several rotation cycles, or different opening and closing switch 202 closing operations are performed in different rotation cycles. Further, the total current flowing through the auxiliary metal electrode 201 each time the opening and closing switch 202 is closed can be controlled by the series resistance component 8, thereby more specifically adjusting the electroplating rate of the wafer surface in the area near the notch of the wafer 105. Its influence range and degree can be flexibly adjusted by selecting the closing time of the opening and closing switch 202 and dynamically adjusting the resistance value of the series resistance component 8, solving the problem of uniformity control in the wafer electroplating process in current semiconductor manufacturing, and being beneficial to improving the yield of the wafer and the economic benefits of production.

[0109] The specific embodiments of the present invention have been described above. Through the above description, relevant staff can make various changes and modifications within the scope of not deviating from the technical idea of the present invention.

Claims

1. An apparatus for adjusting the local electroplating rate of a wafer in an electroplating process, characterized in that, It includes an electroplating component and an electroplating rate adjustment component; The electroplating component includes an electroplating head, an electroplating tank, an anode metal, and a power supply; the electroplating head is used to hold a wafer and can drive the wafer to rotate; the anode metal is arranged in the electroplating tank and is immersed in the electroplating solution during electroplating; the positive electrode of the power supply is electrically connected to the anode metal, and the negative electrode of the power supply is electrically connected to the electroplating head; The electroplating rate adjustment component includes an auxiliary metal electrode and an opening and closing switch. The auxiliary metal electrode is arranged in a specified area in the electroplating tank and is fully or partially immersed in the electroplating solution during electroplating. The auxiliary metal electrode is electrically connected to the negative electrode of the power supply, and the opening and closing switch is arranged on the connection path where the auxiliary metal electrode is located; During the electroplating process, the wafer rotates driven by the electroplating head. During the period when the notch of the wafer rotates to be about to approach and then slightly move away from the specified area where the auxiliary metal electrode is located, control the opening and closing of the opening and closing switch to adjust the electroplating rate around the notch of the wafer.

2. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 1, characterized in that, During the electroplating process, define the position of the wafer in the electroplating tank as the wafer electroplating position; The auxiliary metal electrode is arranged on the side wall of the electroplating tank, and the height of the auxiliary metal electrode is flush with the wafer electroplating position or the auxiliary metal electrode is located between the wafer electroplating position and the anode metal in terms of height.

3. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 1, wherein, The electroplating rate adjustment component further includes a resistance component, and the resistance component is connected in series with the auxiliary metal electrode.

4. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 3, wherein, The resistance component includes one or more resistance units, and each resistance unit includes one or more resistors. When the resistance unit includes multiple resistors, the multiple resistors are connected in series and / or in parallel.

5. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 3, wherein The electroplating rate adjustment component further includes a control module, and the control module is used to control any one or more of the following parameters of the connection path where the auxiliary metal electrode is located: the closing time of the opening and closing switch, the power-on interval, the pulsation frequency, the duty cycle, and the resistance value of the resistance component.

6. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 1, wherein, The shape of the immersed part of the auxiliary metal electrode in the electroplating solution is columnar or fan-shaped; the material of the auxiliary metal electrode is copper, or a specified metal adapted to the composition of the electroplating solution or copper covered with a specified metal on the surface.

7. The device for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 1, characterized in that, The number of the electroplating rate adjustment components is one or more. When the number of the electroplating rate adjustment components is multiple, the auxiliary metal electrodes included in the multiple electroplating rate adjustment components are evenly arranged in the electroplating tank.

8. A method for adjusting the local electroplating rate of a wafer in an electroplating process, characterized in that, Using the device for adjusting the local electroplating rate of a wafer in the electroplating process according to any one of claims 1 to 7, includes the following steps: S10. During the electroplating process, define the position of the wafer in the electroplating tank as the wafer electroplating position. Use the electroplating head to hold the wafer to reach the wafer electroplating position, and control the electroplating head to drive the wafer to rotate at the wafer electroplating position; S20. In each rotation cycle of the wafer, close the opening and closing switch during the period when the notch of the wafer is about to approach and then slightly move away from the specified area where the auxiliary metal electrode is located to adjust the electroplating rate around the notch of the wafer; or after several wafer rotation cycles, then in a certain rotation cycle, close the opening and closing switch during the period when the notch of the wafer is about to approach and then slightly move away from the specified area where the auxiliary metal electrode is located to intermittently adjust the electroplating rate around the notch of the wafer.

9. The method for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 8, wherein, When the auxiliary metal electrode is connected in series with the resistance component and the resistance component includes a plurality of resistors, step S20 further includes: selecting a resistor combination of the resistance component to adjust the electroplating rate around the wafer notch.

10. The method for adjusting the local electroplating rate of a wafer in the electroplating process according to claim 9, characterized in that, When the electroplating rate adjustment component further includes a control module, step S20 further includes: controlling any one or more of the following parameters of the connection path where the auxiliary metal electrode is located through the control module: the closing time of the opening and closing switch, the power-on interval, the pulsation frequency, the duty cycle, and the resistance value of the resistance component.

11. An electroplating device, characterized in that, An apparatus for adjusting the local electroplating rate of a wafer in the electroplating process according to any one of claims 1 to 7.

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