CN-121976276-A - Device and method for improving electroplating uniformity of square wafer

CN121976276ACN 121976276 ACN121976276 ACN 121976276ACN-121976276-A

Abstract

The invention provides a device and a method for improving electroplating uniformity of a square wafer, wherein the device comprises an electroplating assembly and an electroplating rate adjusting assembly, the electroplating assembly comprises a wall, an electroplating bath, anode metal and a power supply and is used for controlling the square wafer to be electroplated vertically, the electroplating rate adjusting assembly comprises an auxiliary electrode, an on-off switch and a frame moving assembly, the position of the auxiliary electrode corresponds to the corner area of the square wafer, the frame moving assembly is connected with the auxiliary electrode and consists of a plurality of moving guide rails in different directions and is used for driving the auxiliary electrode to move in different directions so as to control the auxiliary electrode to be close to or far from the corner area of the square wafer, so that the effect of splitting according to the situation is achieved, electric field intensity differentiation near right angles is further adjusted and optimized, and electroplating uniformity of the corner area of the square wafer is improved.

Inventors

Steven Ho Wang
Yin Qiongling
LIN PENGPENG
WEI YONGYAN
XU YANAN
HUANG YALI

Assignees

芯栋微(上海)半导体技术有限公司

Dates

Publication Date: 20260505
Application Date: 20241025

Claims (10)

1. An apparatus for improving plating uniformity of a square wafer, comprising a plating assembly and a plating rate adjustment assembly; The electroplating assembly comprises a wall, an electroplating bath, anode metal and a power supply, wherein the wall is arranged in the electroplating bath and is used for clamping a square wafer, and the square wafer is vertically immersed in electroplating liquid during electroplating; The electroplating rate adjusting assembly comprises an auxiliary electrode assembly, an on-off switch and a frame moving assembly, wherein the auxiliary electrode assembly comprises a plurality of auxiliary electrodes and an auxiliary electrode frame, the auxiliary electrodes are arranged on the auxiliary electrode frame and are all or partially immersed in electroplating liquid during electroplating, the positions of the auxiliary electrodes on the auxiliary electrode frame correspond to corner areas of square wafers, the on-off switch is arranged on a connecting passage where the auxiliary electrodes are located, and the on-off switch is used for controlling the on-off of the auxiliary electrodes; The frame moving assembly consists of a plurality of moving guide rails in different directions, and is connected with the auxiliary electrode frame and used for driving the auxiliary electrode on the auxiliary electrode frame to move in different directions so as to control the auxiliary electrode to be close to or far away from the corner area of the square wafer; The corner areas of the square wafer refer to the edges and four corners of the square wafer.
2. The apparatus for improving plating uniformity of a square wafer according to claim 1, wherein said wall is capable of holding one or more square wafers.
3. The apparatus for improving plating uniformity of a square wafer according to claim 1, wherein said frame moving assembly comprises three moving parts for controlling movements of the auxiliary electrode frame in x, y, and z directions, respectively, wherein x direction means a left-right movement parallel to a plane of the square wafer, y direction means an up-down movement parallel to the plane of the square wafer, and z direction means a front-back movement perpendicular to the plane of the square wafer.
4. The apparatus for improving plating uniformity of a square wafer according to claim 3, wherein three moving parts are defined as a fixed moving part, an intermediate moving part and a frame moving part, respectively, the fixed moving part is fixed in position, the intermediate moving part connects the fixed moving part and the frame moving part, and the frame moving part connects the auxiliary electrode frame.
5. The apparatus for improving plating uniformity of a square wafer according to claim 4, wherein each of said moving parts comprises a guide rail part and a moving part which are matched, said moving part being movable along the guide rail part matched therewith; the frame moving part is connected with the auxiliary electrode frame through a moving part contained in the frame moving part and is connected with the middle moving part through a guide rail part of the frame moving part, the middle moving part is connected with the fixed moving part and the frame moving part through a guide rail part and a moving part contained in the middle moving part respectively, and the guide rail part of the fixed moving part is fixed in position and is connected with the middle moving part through the moving part.
6. The apparatus for improving plating uniformity of a square wafer according to claim 5, wherein a driving means is provided on each of the moving parts for driving the moving parts to move on the rail parts.
7. The apparatus for improving plating uniformity of a square wafer according to claim 6, wherein said driving means comprises a cylinder or a stepping motor.
8. The apparatus for improving plating uniformity of a square wafer according to claim 1, wherein the auxiliary electrode assembly further comprises a circuit resistor assembly disposed in series with the auxiliary electrode on a connection path between the auxiliary electrode and a negative electrode of a power source, the circuit resistor assembly comprising a fixed resistor assembly or an adjustable resistor.
9. The apparatus for improving electroplating uniformity of a square wafer according to claim 8, wherein the fixed resistor assembly comprises one or more resistor units, each resistor unit comprises one or more resistance fixed resistors, and when the resistor unit comprises a plurality of resistance fixed resistors, the plurality of resistance fixed resistors are connected in series and/or in parallel.
10. A method for improving the plating uniformity of a square wafer, characterized in that the apparatus for improving the plating uniformity of a square wafer according to any one of claims 1 to 9 is used, comprising the steps of: s10, clamping a square wafer by using a hanging wall so that the square wafer is vertically arranged in a plating bath; s20, before electroplating starts, driving the frame moving assembly to drive the auxiliary electrode on the auxiliary electrode frame to move to an initial preset position; S30, in the electroplating process, the square wafer is vertically immersed in the electroplating liquid, the on-off switch is closed to enable the auxiliary electrode to be connected into the circuit, and meanwhile, the frame moving assembly is driven to enable the auxiliary electrode on the auxiliary electrode frame to be driven to move close to or far away from the square wafer.

Description

Device and method for improving electroplating uniformity of square wafer Technical Field The invention relates to the field of wafer electroplating, in particular to a device and a method for improving electroplating uniformity of square wafers. Background Wafer plating is an essential step in semiconductor chip manufacturing and packaging processes. Electroplating is a process of plating a layer of other metals or alloys on the surface of certain metals or other materials by utilizing the electrolysis principle, and the electroplating plays a role in preventing corrosion and improving wear resistance, and particularly, the metal interconnection forms an integrated circuit. Whether the electroplating process is mature or not is an important factor for determining the quality of the electroplated product. The metal electroplating process is widely applied to the application fields of integrated circuits, board-level interconnection and the like, and currently, the fields of Damascus metal interconnection of integrated circuit chips, advanced packaging such as 2.5D/3D integration, fan-in/fan-out packaging and the like generally adopt the electroplating process to deposit and manufacture metal wires and metal contacts. The current electroplating process applied to the integrated circuit semiconductor manufacturing process mainly comprises wafer level horizontal electroplating, namely metal is deposited on the surface of a wafer or a selected area of the surface of the wafer through electroplating equipment and electroplating process, the electroplating equipment mainly comprises an electroplating tank and an electroplating head and other mechanical transmission devices, the electroplating tank is used for bearing electroplating solution and other chemical agents, the electroplating head is used for loading the wafer, the wafer is clamped by the electroplating head in the electroplating process, the surface to be electroplated of the wafer is immersed into electroplating solution of the electroplating tank, an anode metal electrode placed in the electroplating tank and a metal cathode electrode arranged on the electroplating head are enabled to realize an electrochemical reaction current path through the wafer to be electroplated and the electroplating solution, the current of the anode metal electrode is uniformly distributed in the electroplating solution of the electroplating tank, the metal cathode electrode is contacted with a conductive layer on the wafer through a metal contact on the electroplating head, and the electroplating reaction occurs on the electroplating solution and the surface of the wafer to be electroplated, and metal ions are continuously reduced from the electroplating solution to be deposited on the surface of the wafer to be electroplated. In this process, the electroplating rate of each region of the wafer surface needs to be adjusted by controlling the distribution of the current over the whole wafer, i.e. the thickness of the metal deposition in each region is adjusted. In general, in order to obtain better uniformity, the anode metal electrode is divided into different areas to be controlled respectively, and the respective current levels of the anode metal electrodes are adjusted according to the different areas covered by the respective areas to achieve uniform distribution in the whole electroplating bath as much as possible. However, electroplating of certain special wafers, such as square wafers, creates new problems during the electroplating process. The square shape of square wafers (called Wafer squares) causes variations in the electric field intensity distribution around the edges and four corners, which are the main cause of uneven thickness in the result of electroplating such wafers. Because the distance between the electrode and the edge and the four corners of the Wafer square are relatively far, the current density and the solution flow are different from those of the central area, so that the corner current is relatively concentrated, the current transmission and the electroplating effect are affected, and the electroplating homogenization effect of the corners of the square is poor. Disclosure of Invention Aiming at the defects in the prior art, the invention aims to provide a device and a method for improving the electroplating uniformity of square wafers, and the purpose of improving the electroplating uniformity of the corners of the square wafers is realized by setting auxiliary electrodes at the corners of the square wafers to adjust current. In order to achieve the technical effects, the invention adopts the following technical scheme: according to a first aspect of the present invention, there is provided an apparatus for improving plating uniformity of a square wafer, comprising a plating assembly and a plating rate adjustment assembly; The electroplating assembly comprises a wall, an electroplating bath, anode metal and a power supply, wherein the wall i