CN114959843A

CN114959843A - Post-electro-fill module and calibration method for post-electro-fill module

Info

Publication number: CN114959843A
Application number: CN202110191230.0A
Authority: CN
Inventors: 吕泳信; 侯国隆; 林明贤
Original assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Current assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Priority date: 2021-02-19
Filing date: 2021-02-19
Publication date: 2022-08-30

Abstract

A post-electro-fill module and a calibration method for the post-electro-fill module are provided. The calibration method for the post-electro-fill module comprises the following steps: a calibration fixture is disposed above the wafer holder, the calibration fixture including a support, an image detector, and first, second, and third laser light sources. The wafer is arranged on the wafer holder, and the center of the wafer is aligned with the first laser mark emitted by the first laser source. And aligning the second laser mark emitted by the second laser source with the edge of the wafer. A nozzle is disposed above the wafer. And aligning a third laser mark emitted by a third laser source with the nozzle. A first distance between the first laser mark and the second laser mark and a second distance between the first laser mark and the third laser mark are measured by an image detector. It is confirmed whether the difference of the first distance minus the second distance is equal to a predetermined value.

Description

Post-electro-fill module and calibration method for post-electro-fill module

Technical Field

The present disclosure relates to a post-electro-fill module and a calibration method for a post-electro-fill module.

Background

Conductive interconnects on Integrated Circuits (ICs) typically have trenches and vias that are typically formed by either a Damascene process or a Dual-Damascene process. Copper is often used in Ultra Large Scale Integration (ULSI) due to its low resistivity. The standard damascene or dual damascene process is, for example, Electrochemical Copper Deposition (ECD). In particular, Electrochemical plating (ECP) can easily control the growth of the plated film. By way of example, electrochemical plating apparatuses include plating modules, post-electro-fill modules, and the like.

Disclosure of Invention

The present disclosure provides a calibration method for a post-electro-fill module comprising the following operations. Disposing a calibration fixture over the wafer holder, wherein the calibration fixture comprises: a support; an image detector disposed on the bracket and facing the wafer holder; and a first laser light source, a second laser light source and a third laser light source which are respectively arranged on the bracket and face the wafer holder. The wafer is arranged on a wafer holder, wherein the center of the wafer is aligned with a first laser mark emitted by a first laser light source. And aligning the second laser mark emitted by the second laser source with the edge of the wafer. A nozzle is disposed above the wafer. And aligning a third laser mark emitted by a third laser source with the nozzle. The image detector measures a first distance between the first laser mark and the second laser mark and a second distance between the first laser mark and the third laser mark. It is confirmed whether the difference of the first distance minus the second distance is equal to a predetermined value.

The present disclosure provides a calibration method for a post-electro-fill module comprising the following operations. Disposing a calibration fixture over the wafer holder, wherein the calibration fixture comprises: a support; an image detector disposed on the bracket and facing the wafer holder; and a first laser light source and a second laser light source respectively arranged on the bracket and facing the wafer holder. A first laser mark from a first laser light source is aligned to the center of the wafer holder. The wafer is disposed on the wafer holder. A second laser mark from a second laser light source is aligned to the edge of the wafer. The image detector measures the distance between the first laser mark and the second laser mark. It is determined whether the distance is equal to the radius of the wafer.

The present disclosure provides a post-electro-fill module comprising a wafer holder and a calibration fixture disposed above the wafer holder. The calibration device comprises a support, an image detector, a first laser light source, a second laser light source and a third laser light source. The image detector is arranged on the bracket and faces the wafer holder. The first laser light source, the second laser light source and the third laser light source are respectively arranged on the bracket and face the wafer holder.

Drawings

The foregoing and other aspects, features, and advantages of the present disclosure will become more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of a post-electro-fill module, according to various embodiments of the present disclosure;

FIG. 2 is a schematic view of the post-electro-fill module of FIG. 1 with a wafer and nozzle;

FIG. 3A illustrates a top view of a wafer and laser marks according to various embodiments of the present disclosure;

FIG. 3B illustrates a top view of a wafer and laser marks according to various embodiments of the present disclosure;

FIG. 4 is a schematic cross-sectional view of a post-electro-fill module after placement of a wafer and a nozzle in accordance with various embodiments of the present disclosure;

FIG. 5 is a schematic diagram illustrating a post-electro-fill module etching a wafer, according to various embodiments of the present disclosure.

[ notation ] to show

100 rear electric filling module

110 chamber

120 calibration instrument

122, a bracket

124 image detector

126A first laser light source

126B second laser light source

126C third laser light source

130 wafer holder

140 rotating shaft

150 motor

200 wafer

210 nozzle

500 etching solution

D1 first distance

D2 second distance

M1 first laser Mark

M2 second laser marking

M3 third laser marking

Detailed Description

For a more complete and complete description of the present disclosure, reference is now made to the accompanying drawings, in which like numerals represent the same or similar elements, and to the various embodiments described below.

Embodiments of the present disclosure are disclosed below with reference to the accompanying drawings, and for the purposes of clarity, numerous implementation details are set forth in the description below. It should be understood, however, that these implementation details are not to be interpreted as limiting the disclosure. That is, in some embodiments of the disclosure, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner.

Although the methods disclosed herein are illustrated below as a series of acts or steps, the order in which the acts or steps are presented should not be construed as a limitation of the present disclosure. For example, certain operations or steps may be performed in a different order and/or concurrently with other steps. Moreover, not all illustrated operations, steps and/or features may be required to implement an embodiment of the present disclosure. Further, each operation or step described herein may comprise several sub-steps or actions.

Integrated circuit fabrication generally involves depositing more than one metal layer over the active circuit area on a wafer. Conductive interconnect structures on integrated circuits are typically in the form of trenches and vias. These trenches and vias are typically formed by a damascene process or a dual damascene process. In particular, electrochemical plating allows easy control of the plating film growth, which is a common method for forming metal layer deposition because of its bottom-up fill capability and the excellent conductive properties of the plating film, which is well suited for forming small damascene features.

However, during electroplating, the metal layer may be deposited in areas outside the active circuit area, such as the edge area of the wafer. For example, a metal layer is typically deposited as a seed layer prior to electroplating for subsequent electroplating operations, such as Physical Vapor Deposition (PVD) using sputtering, however, to maximize the size of the active circuit area of the wafer, the seed layer must be sputtered very close to the edge of the wafer. Thus, the seed layer covers not only the active circuit area, but also the edge area of the wafer, such as the front edge area and the side of the wafer. In the subsequent electroplating process, a plating metal layer is further formed on the seed layer.

Seed layers remaining at the edge of the wafer are undesirable for a variety of reasons. One reason for this is that the seed layer formed by PVD is thin and therefore tends to flake off during subsequent processing, thus creating undesirable particles or contaminants. At the edge of the wafer, the surface of the wafer is inclined. The seed layers here are not only thin but also deposited unevenly, so they do not adhere well to the wafer. The adhesion of the subsequently formed dielectric layer on the seed layer is also poor, thereby creating the possibility of more particles being generated. In contrast, the seed layer on the active circuit area of the wafer is covered by a thick and uniform electrically-filled metal, which may be exposed by Chemical-mechanical planarization (CMP) to the dielectric. The planar surface, which is primarily a dielectric, may then be further covered with a barrier layer material, such as silicon nitride (SiN), which adheres well to the dielectric and may aid in adhesion of subsequent layers. In summary, the metal in the edge area has poor adhesion compared to the metal in the active circuit area, and may peel off during the subsequent process, thereby generating undesirable particles and affecting the process.

The metal in the edge region of the wafer may adversely affect subsequent processing. To address this problem, after the wafer is electroplated, Edge Bevel Removal (EBR) may be performed on the Edge region of the wafer to remove the seed layer and the electroplated metal layer. Edge bevel removal is typically performed in a Post electro fill module (PEM).

The accuracy of the edge bevel removal operation is important in that it does not remove too much or too little metal from the edge region of the wafer. Accuracy may be affected by the following two factors. First, alignment and centering of the wafer with the wafer holder of the post-electro-fill module is important because if the wafer is not centered, the edge bevel removal operation cannot symmetrically remove the metal in the edge region. Second, during the edge bevel removal operation, the nozzles providing the etching solution are required to be placed on the edge area of the wafer, and the size of the area where the metal is removed is also affected if the nozzles are accurately placed on the predetermined positions. An effective edge bevel removal operation is used to remove metal from the edge region as completely and radially symmetrically as possible to avoid defects associated with the metal in the edge region.

The present disclosure provides a rear electro-fill module. The electrofill module may thereafter be part of an electroplating system. Electroplating systems are generally a wafer processing system used to form a layer of electroplated metal on a wafer by an electroplating operation. The post-electro-fill module is generally a wafer processing apparatus used to further process the wafer after a layer of plated metal has been formed on the surface of the wafer by a plating operation. The back electro-fill module typically includes components that allow for edge bevel removal. The device may perform, for example, Backside etch (BSE) and ancillary processes such as preclean, clean, acid clean, and dry.

In particular, the plating operation may be performed by a plating module. The electroplating module generally comprises: an electroplating bath and a wafer holder. The plating bath is used to contain the anode and electrolyte during plating. The wafer holder is used to hold a wafer in an electroplating solution during electroplating and to rotate the wafer. One electrode (anode) in the electrolyte will undergo oxidation and the other electrode (cathode) will undergo reduction. In some embodiments, the anode is a copper anode and the wafer is a cathode. The metal of the copper anode will oxidize and become ionic. At the wafer, the metal ions in the electrolyte will accept one or more electrons from the wafer and the ions are reduced to form a solid metal (i.e., copper) that is electrodeposited on the wafer. Thus, the wafer disposed in the plating bath is plated to form interconnect features on the wafer.

In some embodiments, the electroplating system may also include a chemical dilution module, a center electrofill bath, and a dosing system. The chemical dilution module may store and mix chemicals for use as etchants in the post-electro-fill module. The central electro-fill bath may be a tank containing the chemical solution for the plating bath in the electro-fill module. The reagent system is used to store and deliver chemical additives for the plating bath. In some embodiments, a method of performing edge bevel removal includes pre-rinsing a rotating wafer with a pre-rinse comprising deionized water, and then delivering a dilution stream over an edge bevel to dilute the pre-rinse layer. The diluent may alter the properties of the preflush, for example, reduce its surface tension and/or viscosity, increase its temperature and/or vapor pressure, and the like. Thereafter, an etching solution is delivered onto the edge of the wafer such that the etching solution flows selectively over the edge bevel region. The etching liquid passes through the residual pre-rinse liquid layer and etches away the unwanted metal on the bevel edge region.

Referring to fig. 1, fig. 1 is a schematic diagram illustrating a rear electro-fill module 100 according to some embodiments of the present disclosure. The rear electro-fill module 100 includes a chamber 110, a calibration fixture 120, a wafer holder 130, a rotating shaft 140, and a motor 150. The calibration fixture 120 is disposed above the wafer holder 130. The calibration tool 120 includes a support (Jig)122, an image detector 124, and a first laser source 126A, a second laser source 126B, and a third laser source 126C. The image detector 124 is disposed on the support 122 toward the wafer holder 130. The first, second and third

laser light sources

126A, 126B, 126C are disposed on the support 122, respectively, facing the wafer holder 130. The rotation shaft 140 is disposed between the wafer holder 130 and the motor 150. The motor 150 should be easy to control and should transition smoothly between various different rotational speeds. The wafer holder 130 provides rotational motion of the wafer (not shown).

In some embodiments, the first laser source 126A, the second laser source 126B and the third laser source 126C are rotatably disposed on the support 122, so that the irradiation direction of the laser sources is adjustable. In detail, the first laser source 126A, the second laser source 126B and the third laser source 126C can be rotated to change the included angle between the irradiation direction and the lower surface of the support 122. In some embodiments, the image detector 124 is a Charge Coupled Device (CCD). In other embodiments, the post-electro-fill module 100 further comprises a nozzle (not shown in fig. 1) disposed between the wafer holder 130 and the calibration fixture 120. Details regarding the nozzle will be further described in the embodiment of fig. 2, which follows. In some embodiments, the first laser light source 126A is disposed in the center of the support 122. In some embodiments, the first laser light source 126A is substantially aligned with the center of the wafer holder 130.

In some embodiments, chamber 110 may include an etchant resistant material and include ports and nozzles for various liquid and gas flows used during etching and cleaning. The chamber 110 may have any suitable design to confine fluids (e.g., etchants) therein and to allow delivery of various fluids to the wafer. In some embodiments, chamber 110 is provided with a discharge line (not shown). The drain line enables various liquids provided to the chamber 110 to be drained out of the chamber 110 for waste treatment.

In some embodiments, the wafer holder 130 is designed to be able to hold the wafer securely in place and to be rotated and accelerated at various rotational speeds ranging from about 0RPM to about 6000 RPM. The wafer holder 130 may also assist in alignment of the wafer for the etching process.

In some embodiments, to prevent damage from the liquid etchant, the motor 150 is disposed outside the chamber 110, as shown in fig. 1. The motor 150 may be further separated from the chamber 110 by a seal (not shown). Through which the rotating shaft 140 passes. In other embodiments, the motor 150 is disposed within the chamber 110. In some implementations, the motor 150 can rapidly accelerate and decelerate the wafer holder 110 at a rotation rate between about 0RPM and about 6000 RPM. In some embodiments, a controller operates and controls the motor and its speed. Generally, the effective speed range for the Edge Bevel Removal (EBR) procedure disclosed herein is from about 0RPM to about 2500RPM, or from about 100RPM to about 1500RPM, or from about 500RPM to about 1300 RPM.

Some embodiments of the present disclosure provide a calibration method for a post-electro-fill module. Fig. 2 is a schematic diagram illustrating the placement of the wafer 200 and the nozzle 210 on the back electro-fill module 100 shown in fig. 1. Fig. 3A illustrates a top view of a wafer 200 and laser marks according to some embodiments of the present disclosure.

The calibration method for the post-electro-fill module comprises the following operations: operation (a): the calibration fixture 120 is disposed above the wafer holder 130, wherein the calibration fixture 120 includes a support 122, an image detector 124, and a first laser light source 126A, a second laser light source 126B, and a third laser light source 126C. The image detector 124 is disposed on the support 122 toward the wafer holder 130. The first, second and third

laser light sources

126A, 126B and 126C are respectively disposed on the bracket 122 facing the wafer holder 130. Operation (b): the wafer 200 is disposed on the wafer holder 130, wherein the wafer 200 is centered on the first laser mark M1 emitted from the first laser source 126A. Operation (c): the second laser mark M2 emitted by the second laser source 126B is aligned with the edge of the wafer 200. Operation (d): a nozzle 210 is disposed above the wafer 200. Operation (e): the third laser mark M3 emitted from the third laser light source 126C is aligned with the nozzle 210. Operation (f): the image detector measures a first distance D1 between the first laser mark M1 and the second laser mark M2 and a second distance D2 between the first laser mark M1 and the third laser mark M3. Operation (g): it is confirmed whether the difference of the first distance D1 minus the second distance D2 is equal to a predetermined value. In some embodiments, when the difference is not equivalent to the predetermined value, the position of the nozzle is adjusted to make the difference equivalent to the predetermined value. In some embodiments, the predetermined value is about 1 millimeter (mm) to about 2.8 mm. The size of the preset value can be adjusted according to design requirements.

In some embodiments, the nozzle 210 is connected to a liquid etchant source (not shown) for providing liquid etchant to the wafer for Edge Bevel Removal (EBR) to selectively remove unwanted metal (e.g., metal deposited by PVD or electroplating) from the edge bevel region of the wafer 200. For example, the etching solution includes an acid and an oxidizing agent. Examples of useful acids include sulfuric acid, hydrohalic acid, chromic acid, and nitric acid. In one embodiment, the etchant for copper EBR may be sulfuric acid (H) ₂ SO ₄ ) And hydrogen peroxide (H) ₂ O ₂ ). In some embodiments, the etching solution comprises between about 15% to about 25% by weight of H ₂ SO ₄ To between about 20% to about 35% by weight of H ₂ O ₂ . The thinner the film of the pre-rinse liquid, the higher the acid concentration in the etching solution. Other oxidants may be used, such as peroxodisulfates and concentrated nitric acid HNO ₃ (about 30% to about 35% in water). In detail, the liquid etching solution is delivered to the wafer 200 through a flow meter and through the pipeline and the nozzle 210.

As shown in fig. 2, the nozzle 210 has an outward nozzle, so that the etching solution etches the third laser mark M3 to a width of an annular region defined by the edge of the wafer, which is a difference between the first distance D1 and the second distance D2. The etchant removes metal near the edge of the wafer with rotation. The calibration method for the post-electro-fill module of the present disclosure can detect the laser mark in real time by the image detector 124 to precisely determine the position of the nozzle 210, so as to precisely remove the metal at the edge to be removed. In some embodiments, referring to fig. 2 and 3A, the axial direction of the nozzle 210 includes an angle with respect to the second distance D2. The angle is between about 10 ° and about 80 °. The angle can be adjusted as required to remove a predetermined amount of metal from the etching solution sprayed from the nozzle 210.

In some embodiments, the first laser mark M1 emitted by the first laser source 126A is aligned with the center of the wafer holder 130 before the wafer 200 is placed on the wafer holder 130. Through this operation, it may be ensured that the first laser mark M1, the center of the wafer holder 130, and the center of the wafer 200 are aligned with each other. Alignment and centering of the wafer 200 with the wafer holder 130 of the rear electro-fill module 100 is important, and after the wafer 200 is precisely centered, the edge bevel removal operation symmetrically removes the metal in the edge region.

Fig. 4 illustrates a cross-sectional view of the back electro-fill module 100 after placement of the wafer 200 and the nozzle 210, according to some embodiments of the present disclosure. FIG. 5 shows a schematic diagram of the post-electro-fill module 100 etching a wafer 200 according to various embodiments of the present disclosure. As shown in FIG. 5, the nozzle 210 has an outward nozzle, and the liquid etchant 500 is sprayed from the nozzle 210 to remove metal near the edge of the wafer. In detail, the liquid etching solution 500 is applied to the edge of the wafer in a trickle manner, so that the liquid etching solution 500 maintains a thin viscous layer on the wafer 200 near the application position thereof, thereby preventing the liquid etching solution 500 from splashing to the inside of the wafer 200 and removing the metal in the effective circuit area. It is important to uniformly apply the liquid etchant 500, which may otherwise result in variations in the dimensions of the metal regions to be removed. A substantially uniform area of metal to be removed may result in a maximum effective and usable surface area. Because the liquid etchant is generally applied with a radial velocity component, and because of the centripetal acceleration effect of the spinning wafer 200, the thin viscous layer flows outward, down over the edge and possibly also onto the back side of the wafer 200, thus achieving the purpose of removing metal from the edge of the wafer. In some embodiments, EBR is performed under the following conditions: for wafers having a diameter of about 290 mm to about 310 mm, a total of about 3 ml to about 15 ml of liquid etchant is delivered at a rate of about 0.2 ml/sec to about 3 ml/sec, preferably about 0.3 ml/sec to about 0.4 ml/sec. In some embodiments, the liquid etchant may be provided through two or more operations, wherein the flow rate of the liquid etchant is different in different operations. For example, in the first operation, about 1 ml/s to about 2 ml of the liquid etching solution is provided at about 0.4 ml/s to about 0.5 ml/s, and then, in the second operation, about 8 ml/s to about 12 ml of the liquid etching solution is provided at about 0.2 ml/s to about 0.4 ml/s.

In some embodiments, after Edge Bevel Removal (EBR), the electroplated metal is planarized, typically by Chemical-mechanical planarization (CMP), in preparation for further incorporation of subsequent dielectric and metallization layers.

The following are gases and liquids that may be introduced into chamber 110. Gaseous nitrogen or other non-reactive gas may be provided from a gas source into the chamber 110 of the back electro-fill module 100. In detail, nitrogen from a gas source may be delivered into the chamber 110 through a nozzle (not shown) under the control of a valve. The nozzle is typically above the wafer 200 with the nozzle facing downward to deliver nitrogen to the wafer 200 in a downward direction, which further accelerates the drying process. The wafer holder 130 may be rotated at a rotation speed of about 4500RPM to about 5500RPM during the rotation/cleaning/drying.

In addition, an acid wash may be performed on the front side of the wafer 200. For example, sulfuric acid may be provided from a sulfuric acid source into the chamber 110 of the post-electro-fill module 100. Other acids may be used, or may be used in combination with sulfuric acid. For example, hydrogen peroxide may be used. Notably, the nozzle providing the sulfuric acid is oriented to direct the sulfuric acid onto the center of the front side of the wafer 200. After the sulfuric acid is delivered to the center of the wafer, it is then spun out into the edge of the wafer during rotation. This solution can be applied to remove residual metal oxide remaining after oxidizing (etching) the wafer, as well as to assist in the overall wafer cleaning step. Only relatively small amounts of acid are generally required. After this application, the front side of the wafer 200 is rinsed with deionized water.

In some embodiments, the wafer is typically pre-rinsed prior to Edge Bevel Removal (EBR) to convert the dry or partially wetted edge and edge bevel to a uniformly wetted wafer edge. The pre-rinse may be, for example, deionized water. Deionized water may be provided into the chamber 110 of the post-electro-fill module 100 from a deionized water source. In detail, deionized water may be delivered into the chamber 110 through a nozzle (not shown) under the control of a valve. Notably, the lines and nozzles direct deionized water onto the top of the wafer 200, which may clean the top of the wafer. In some embodiments, the etchant may flow unevenly over the edges along sparsely wetted areas if not pre-rinsed. Thus, without a uniform and completely wetted edge, the effect of edge bevel removal can be compromised. However, after the pre-rinse is delivered to the wafer surface, the fluid is driven radially outward due to centrifugal forces and surface tension tends to hold the pre-rinse on the wafer, so the pre-rinse tends to accumulate at the wafer edge (bevel). In some embodiments, deionized water is applied to the wafer 200 prior to providing the liquid etchant, wherein the wafer 200 is rotated at about 200RPM to about 600RPM to pre-clean the wafer 200 of any particles and contaminants left from previous operations. Next, the deionized water source is turned off and the wafer is rotated at a speed of about 350RPM to about 500RPM, which results in a uniform thin layer of deionized water on the surface of the wafer 200. This wet film stabilization may facilitate uniform distribution of etchant on the wafer 200. In some embodiments, after providing the liquid etchant, deionized water is applied to the wafer 200 to act as a post EBR clean to protect the wafer from any excess backside etchant spray and damage. In some embodiments, the pre-flush operation is performed for a time period of between about 1 second and about 5 seconds and at a flow rate of between about 200 ml/min and about 800 ml/min. It is sometimes desirable to use hot rinse water to improve the pre-rinse efficiency. Thus, deionized water at about 20 ℃ to about 50 ℃ may be used.

In some embodiments, a Backside etching (BSE) operation is performed after EBR. For example, the BSE operation may be performed using the same liquid etchant as used for the EBR. In detail, the BSE operation may include the following operations: a liquid etchant is injected toward the center of the back side of the wafer 200. The liquid etchant is delivered, for example, from a tubular nozzle having a diameter of about 0.02 inches to about 0.04 inches and a length of at least about 4 to about 5 diameters. The liquid etchant then covers the entire back surface of the wafer 200. The purpose of the BSE operation is to remove any residual metal (e.g., copper) formed on the wafer backside during deposition of the seed layer.

Etchants for BSE are typically applied using a spray nozzle. Since the arm of the wafer holder 130 may interfere with spraying the liquid etchant on the backside of the wafer 200, the angle of the spray nozzles may be adjusted during BSE to ensure complete application of the liquid etchant. This process is typically performed at two different speeds to ensure that the liquid etchant flows properly over the entire backside of the wafer 200. For example, during one portion of the BSE, the wafer 200 is rotated at about 300RPM to about 400RPM, and during another portion, the wafer 200 is rotated at about 500RPM to about 700RPM to ensure complete coverage. The BSE process typically takes about 1 to about 4 seconds and uses a liquid etchant of about 1 to about 5 cubic centimeters or less.

In some embodiments, after the BSE operation, both sides of the wafer 200 (or at least the backside of the wafer) are cleaned with deionized water to clean away any liquid etchant, particles, and contaminants remaining from the BSE operation. In some embodiments, after the deionized water supply is terminated, a diluted acid is further applied to the front surface of the wafer 200 to remove the residual metal oxide. In particular embodiments, the acid is applied at a rate of about 1 ml/sec to about 3 ml/sec. After the acid wash, deionized water may again be applied to both sides, or at least the front surface, of the wafer 200 to wash the acid from the wafer. In a particular embodiment, the deionized water is applied at about 300 ml/min to about 400 ml/min for about 15 seconds to about 30 seconds. Next, the wafer 200 may be spun and the wafer 200 may be further blown dry with nitrogen as desired. For example, the drying step is performed at about 750RPM to about 2000RPM for about 10 seconds to about 60 seconds.

After processing in the post-electro-fill module 100, a robot arm may be used to pick up the wafer 200 and place it in a cassette for transfer to other modules of the electroplating system for subsequent additional processing.

The present disclosure provides another calibration method for a post-electro-fill module. Fig. 2 is a schematic diagram illustrating the placement of the wafer 200 and the nozzle 210 on the back electro-fill module 100 shown in fig. 1. Fig. 3B illustrates a top view of the wafer 200 and laser marks according to various embodiments of the present disclosure.

The calibration method for the post-electro-fill module comprises the following operations: operation (a): the calibration fixture 120 is disposed above the wafer holder 130, wherein the calibration fixture 120 includes a support 122, an image detector 124, and a first laser light source 126A and a second laser light source 126B. The image detector 124 is disposed on the support 122 toward the wafer holder 110. Operation (b): the first laser mark M1 from the first laser light source 126A is aligned with the center of the wafer holder 130. Operation (c): the wafer 200 is disposed on the wafer holder 130. Operation (d): the second laser mark M2 from the second laser light source 126B is aligned with the edge of the wafer 200. Operation (e): the image detector 124 measures a first distance D1 between the first laser mark M1 and the second laser mark M2. Operation (f): it is determined whether the first distance D1 is equal to the radius R of the wafer.

Through the above operation, it may be confirmed whether the center of the wafer 200 is aligned with the center of the wafer holder 130. Alignment and centering of the wafer 200 with the wafer holder 130 of the rear electro-fill module 100 is important, and after the wafer 200 is precisely centered, the edge bevel removal operation symmetrically removes the metal in the edge region. In some embodiments, when the first distance D1 is not equal to the radius R of the wafer 200, the position of the wafer 200 is adjusted such that the first distance D1 is equal to the radius R of the wafer 200. Through the above operation, the center of the wafer 200 may be aligned with the center of the wafer holder 130.

Next, please refer to fig. 2 and fig. 3A again. In some embodiments, the nozzle 210 is positioned above the wafer 200 after determining whether the first distance D1 is equal to the radius R of the wafer 200. The third laser mark M3 from the third laser light source 126C is aligned with the nozzle 210. The image detector 124 measures a second distance D2 between the first laser mark M1 and the third laser mark M3. It is confirmed whether the difference of the first distance D1 minus the second distance D2 is equal to a predetermined value. In some embodiments, when the difference is not equal to the predetermined value, the position of the nozzle 210 is adjusted to make the difference equal to the predetermined value. In some embodiments, the predetermined value is about 1 millimeter (mm) to about 2.8 mm. The size of the preset value can be adjusted according to design requirements.

The calibration method for the post-electro-fill module of the present disclosure can detect the laser mark in real time by the image detector 124 to precisely determine the position of the nozzle 210, so as to precisely remove the metal at the edge to be removed. Thus, the edge bevel removal operation may be used to remove metal from the edge region as completely and radially symmetrically as possible.

Fig. 4 illustrates a cross-sectional view of the back electro-fill module 100 after placement of the wafer 200 and the nozzle 210, according to various embodiments of the present disclosure. Fig. 5 is a schematic diagram illustrating the etching of the wafer 200 by the post-electro-fill module 100 according to various embodiments of the present disclosure. As shown in FIG. 5, the nozzle 210 has an outward nozzle, and the liquid etchant 500 is sprayed from the nozzle 210 to remove metal near the edge of the wafer. In detail, the liquid etching solution 500 is applied to the edge of the wafer in a trickle manner, so that the liquid etching solution 500 maintains a thin viscous layer on the wafer 200 near the application position thereof, thereby preventing the liquid etching solution 500 from splashing to the inside of the wafer 200 and removing the metal in the effective circuit area. It is important to uniformly apply the liquid etchant 500, which may otherwise result in variations in the dimensions of the metal regions to be removed. A substantially uniform area of metal to be removed may result in a maximum effective and usable surface area. Because the liquid etchant is generally applied with a radial velocity component, and because of the centripetal acceleration effect of the spinning wafer 200, the thin viscous layer flows outward, down over the edge and possibly also onto the back side of the wafer 200, thus achieving the purpose of removing metal from the edge of the wafer.

In summary, the present disclosure provides a post-electro-fill module and a calibration method for the post-electro-fill module. The back electric filling module is provided with a correcting device provided with an image detector, and the image detector can be used for detecting the wafer center, the wafer edge and the position of the nozzle corresponding to the laser mark in real time, so that whether the wafer is positioned correctly during wafer placing can be confirmed, and whether the placing position of the nozzle is as expected can also be confirmed. The calibration method of the present disclosure is more accurate than adjusting the sheet placement position and the nozzle position visually.

The present disclosure provides a calibration method for a post-electro-fill module comprising the following operations. Disposing a calibration fixture over the wafer holder, wherein the calibration fixture comprises: a support; an image detector disposed on the bracket and facing the wafer holder; and a first laser light source, a second laser light source and a third laser light source which are respectively arranged on the bracket and face the wafer holder. The wafer is arranged on the wafer holder, wherein the center of the wafer is aligned with the first laser mark emitted by the first laser source. And aligning the second laser mark emitted by the second laser source with the edge of the wafer. A nozzle is disposed above the wafer. And aligning a third laser mark emitted by a third laser source with the nozzle. The image detector measures a first distance between the first laser mark and the second laser mark and a second distance between the first laser mark and the third laser mark. It is confirmed whether the difference of the first distance minus the second distance is equal to a predetermined value.

In some embodiments, the calibration method for the post-electro-fill module further comprises: when the difference is not equivalent to the predetermined value, the position of the nozzle is adjusted so that the difference is equivalent to the predetermined value.

In some embodiments, the calibration method for the post-electro-fill module further comprises: before the wafer is arranged on the wafer holder, a first laser mark emitted by a first laser source is aligned with the center of the wafer holder.

In some embodiments, the calibration method for the post-electro-fill module further comprises: when the distance is not equal to the radius of the wafer, the position of the wafer is adjusted to make the distance equal to the radius of the wafer.

In some embodiments, the first laser light source, the second laser light source, and the third laser light source are rotatably disposed on the support.

In some embodiments, the back electro-fill module further comprises: the nozzle is disposed between the wafer holder and the aligner.

In some embodiments, the first laser light source is disposed in the center of the holder.

In some embodiments, the first laser light source is substantially aligned with the center of the wafer holder.

Although the present disclosure has been described in considerable detail with reference to certain embodiments, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

It will be apparent to those skilled in the art that various modifications and variations can be made in the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure that fall within the scope of the appended claims.

Claims

1. A calibration method for a post-electro-fill module, comprising:

disposing a calibration fixture over a wafer holder, wherein the calibration fixture comprises:

a support;

an image detector disposed on the support and facing the wafer holder; and

a first laser source, a second laser source and a third laser source respectively arranged on the bracket and facing the wafer holder;

arranging a wafer on the wafer holder, wherein a center of the wafer is aligned with a first laser mark emitted by the first laser source;

aligning a second laser mark emitted by the second laser source to an edge of the wafer;

arranging a nozzle above the wafer;

aligning a third laser mark emitted by the third laser source with the nozzle;

measuring a first distance between the first laser mark and the second laser mark and a second distance between the first laser mark and the third laser mark by using the image detector; and

determining whether a difference between the first distance and the second distance is equal to a predetermined value.

2. The method of claim 1, further comprising: when the difference is not equal to the predetermined value, the position of the nozzle is adjusted so that the difference is equal to the predetermined value.

3. The method of claim 1, further comprising: before the wafer is arranged on the wafer holder, the first laser mark emitted by the first laser source is aligned with the center of the wafer holder.

4. A calibration method for a post-electro-fill module, comprising:

a support;

an image detector disposed on the support and facing the wafer holder; and

a first laser light source and a second laser light source respectively arranged on the bracket and facing the wafer holder;

aligning the first laser mark from the first laser light source to a center of the wafer holder;

disposing a wafer on the wafer holder;

aligning a second laser mark from the second laser source to an edge of the wafer;

measuring a distance between the first laser mark and the second laser mark by the image detector; and

it is determined whether the distance is equal to the radius of the wafer.

5. The method of claim 4, further comprising: when the distance is not equal to the radius of the wafer, the position of the wafer is adjusted to make the distance equal to the radius of the wafer.

6. A rear electro-fill module, comprising:

a wafer holder; and

a calibration fixture disposed above the wafer holder, wherein the calibration fixture comprises:

a support;

an image detector disposed on the support, the image detector facing the wafer holder; and

a first laser light source, a second laser light source and a third laser light source respectively arranged on the bracket and facing the wafer holder.

7. The rear electro-fill module of claim 6, wherein the first, second and third laser light sources are rotatably disposed on the bracket.

8. The rear electro-fill module of claim 6, further comprising: a nozzle is disposed between the wafer holder and the aligner.

9. The rear electro-fill module of claim 6, wherein the first laser light source is disposed in the center of the support.

10. The rear electro-fill module of claim 9, wherein the first laser light source is aligned with a center of the wafer holder.