KR20030058578A - Electrochemical-mechanical Polishing Device for Controlling Reactivity of Slurry - Google Patents

Abstract

PURPOSE: An electrochemical mechanical polishing(ECMP) apparatus for controlling slurry reactivity is provided to control electrochemical reactivity on a wafer by forming metal electrodes in a polishing pad and at the end of a retainer ring so that the wafer functions as a working electrode and the metal in the polishing pad functions as a counter electrode. CONSTITUTION: The metal electrode is formed at the end of the retainer ring(20) so as to be electrically connected to the wafer(22). An inner metal(12) is formed under the polishing pad(10) and in the vicinity of a slurry exhausting hole. The first and second electrodes of a power unit(30) are respectively formed in the metal electrode of the retainer ring and the inner metal of the polishing pad wherein the voltage and current of the power unit is controllable. A slurry exhausting apparatus(40) supplies the slurry including an electrolyte component to the polishing pad.

Description

Electrochemical-mechanical Polishing Device for Controlling Reactivity of Slurry

The present invention relates to an electrochemical-mechanical polishing (ECMP) apparatus used in a semiconductor process, and more particularly, to an ECMP apparatus capable of controlling the electrochemical reactivity of a wafer surface and a slurry by adjusting voltage and current from the outside.

The CMP process, which is generally used in the semiconductor process, is performed by directly adhering the polishing pad attached to the table rotating at the bottom and the wafer fixed in the retainer ring of the upper head portion. During the polishing process, a slurry solution that is chemically reactive with the abrasive is sprayed while maintaining a constant rotational speed of the polishing pad and the table and a pressure applied downwardly of the head. As the chemical reaction of the slurry increases the reactivity of the metal, the slurry is an oxidizer for oxidizing the metal surface to mechanically remove the oxide film, and a composite agent for preventing re-adhesion of metal ions present in the slurry during oxidation. Many inclusions should include complexing agents, corrosion inhibitors that inhibit corrosion of metal surfaces, and surfactants that promote surface adsorption to enhance reactivity. In addition, there is a problem that there are many limitations in the development of the slurry due to the limitation of the chemical action between the various components illustrated above.

The present invention is to solve the above problems, by forming a metal electrode inside the polishing pad and the end of the retainer ring, so that the wafer acts as a working electrode, the metal inside the polishing pad as a counter electrode. Accordingly, an object of the present invention is to provide an ECMP apparatus capable of controlling the electrochemical reactivity of the wafer surface and a method of controlling the reactivity of the slurry using the ECMP apparatus.

1 is a diagram of an ECMP apparatus according to an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

10 polishing pad 12 internal metal

20: retainer ring 22: wafer

23: internal electrode 30: power

40: slurry discharge device

In order to achieve the above object, an ECMP apparatus according to the present invention comprises a retainer ring having a metal electrode electrically connected to the wafer at the end; A polishing pad having an inner metal formed around the lower portion and the slurry outlet; A power supply unit having a first pole and a second pole connected to the metal electrode of the retainer ring and the inner metal of the polishing pad, respectively, and having a voltage and a current supplied thereto adjustable; And a slurry discharge device for supplying a slurry containing an electrolyte component to the polishing pad.

In addition, the method of controlling the reactivity of the slurry according to the present invention, in the CMP process,

Using a slurry comprising an electrolyte; Installed on a retainer ring supporting the wafer, and applying power to an internal metal electrically connected to the wafer and the internal metal provided on the polishing pad; It is characterized by controlling the electrochemical reactivity of the slurry by controlling the current and voltage of the power source.

The above and other objects and features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an ECMP apparatus according to an embodiment of the present invention. The ECMP apparatus includes a polishing pad 10, an internal metal 12, a retainer ring 20, a wafer 22, an internal electrode 23, a power supply 30, and a slurry discharge device 40. The retainer ring 20 to which the wafer 22 is fixed is formed with a metal electrode 23 at an end thereof, and the inner electrode 23 is connected to the anode of the power supply 30 and fixed to the retainer ring 20 ( 22) is electrically connected. At this time, even when the wafer is supported by a structure other than the retaining ring 20, the wafer only needs to be electrically connected to the power source.

The polishing pad 10 is generally formed with an outlet for discharging the slurry supplied from the slurry discharging device 40 to the surface of the wafer 22. In order to apply voltage and current to the slurry, the polishing pad 10 A part of the inner metal 12 is formed to be connected to the power source 30. Preferably, the inner metal 12 may be formed in a shape to surround the discharge port which is the lower and side portions of the polishing pad 10 as shown. It is also desirable to select a chemically stable metal to prevent the slurry and metal from reacting.

The slurry discharge device 40 supplies the slurry to the surface of the polishing pad 10 and the surface of the wafer 22 through an outlet formed in the polishing pad 10. However, the slurry must include an electrolyte in order to control the reactivity by the current and voltage applied between the wafer 22 and the polishing pad 10 through the internal electrode 23 and the internal metal 12. Preferably, the electrical conductivity of the slurry may be 100 ?? S / cm or more. More preferably, the slurry may change its chemical properties through applied current and voltage, and thus may not include abrasives, oxidants, or surfactants.

Referring to the method of controlling the reactivity of the slurry using the ECMP apparatus according to the present invention. In the CMP process, the internal electrode 23 and the polishing pad 10 are provided in the retainer ring 20 supporting the wafer 22 using a slurry containing an electrolyte and electrically connected to the wafer 22. The power supply 30 is applied to the internal metal 12 installed in the power supply, and the voltage and current applied between the wafer 22 and the polishing pad 10 by controlling the current and the voltage of the power supply 30 to control the electricity of the slurry. Chemical reactivity can be controlled. That is, the wafer 22 electrically connected to the anode of the power supply 30 through the internal electrode 23 of the retainer ring 20 is a working electrode and a cathode of the power supply 30. By applying the inner metal 12 in the polishing pad 10 electrically connected to the counter electrode, voltage and current are applied to the slurry serving as the electrolyte. Accordingly, the CMP process can be finely controlled by easily adjusting the electrochemical reactivity of the slurry and the surface of the wafer 22 by adjusting the voltage and current supplied from the power supply 30.

Preferably, the method may further include a function of detecting an end point of the CMP process by monitoring a change in current and voltage applied to the slurry, and more preferably, the power supply unit 30 controls the current and voltage applied to the slurry. In addition, the method may further include a function of removing particles, ions, and metal impurities adsorbed on the surface of the wafer 22 by a reverse method.

As described above, according to the method of controlling the reactivity of the ECMP apparatus and the slurry according to the present invention, since the voltage and current can be applied to the slurry compared to the conventional CMP method which improves the reactivity only chemically, the oxidizing agent and the surfactant in the slurry It is possible to dramatically reduce the components of the back and the like, and to use the same slurry in a process requiring different reactivity, but it is possible to enable various reactions of the wafer and the slurry by a simple method of controlling the current and voltage. In addition, preferred embodiments of the present invention are disclosed for purposes of illustration, and various modifications, changes, additions, and the like may be made by those skilled in the art within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

Claims (15)

In the CMP apparatus, A retainer ring having a metal electrode electrically connected to the wafer at an end thereof; A polishing pad having an inner metal formed around the lower portion and the slurry outlet; A power supply unit having a first pole and a second pole connected to the metal electrode of the retainer ring and the inner metal of the polishing pad, respectively, and having a voltage and a current supplied thereto adjustable; And CMP device comprising a slurry discharge device for supplying a slurry containing an electrolyte component to the polishing pad The method of claim 1, And wherein the first pole is an anode and the second pole is a cathode. The method according to claim 1 or 2, The slurry is a CMP apparatus, characterized in that the electrical conductivity is 100 ?? S / cm or more. The method according to claim 1 or 2, The slurry is CMP apparatus, characterized in that no abrasive is included. The method according to claim 1 or 2, The slurry is CMP apparatus, characterized in that it does not contain an oxidizing agent, a surfactant. The method of claim 3, wherein The slurry is CMP apparatus, characterized in that it does not contain an oxidizing agent, a surfactant. The method according to claim 1 or 2, And a detection device for detecting an end point of the CMP process by monitoring changes in current and voltage applied to the slurry. The method according to claim 1 or 2, And the power supply unit further includes a function of removing particles, ions, and metal impurities adsorbed on the surface of the wafer by adjusting and reversing current and voltage applied to the slurry. The method of claim 7, wherein The power supply unit further comprises a function of removing particles, ions and metal impurities adsorbed on the wafer surface by controlling and reversing the current and voltage applied to the slurry. In the CMP process, Using a slurry comprising an electrolyte; A power supply is applied to an internal metal installed in the retainer ring supporting the wafer and electrically connected to the wafer and the polishing pad; And controlling the electrochemical reactivity of the slurry by controlling the voltage and current applied between the wafer and the polishing pad by adjusting the current and voltage of the power source. The method of claim 10, Reactivity control method of the slurry, characterized in that the electrical conductivity of the slurry is 100 ?? S / cm or more. The method of claim 10 or 11, The slurry is a reactive control method of the slurry, characterized in that it does not contain an oxidizing agent and a surfactant. The method of claim 10 or 11, Reactive control method of the slurry characterized in that it further comprises a function of detecting the end point of the CMP process by monitoring the change in the current and voltage applied to the slurry. The method of claim 10 or 11, And the power supply unit further includes a function of removing particles, ions, and metal impurities adsorbed on the wafer surface by controlling and reversing current and voltage applied to the slurry. The method of claim 13, And the power supply unit further includes a function of removing particles, ions, and metal impurities adsorbed on the wafer surface by controlling and reversing current and voltage applied to the slurry.