Chemical Mechanical Polishing Apparatus

This application claims priority to Korean Patent Application No. 10-2024-0039286 filed in the Korean Intellectual Property Office on Mar. 21, 2024, the disclosure of which is incorporated herein in its entirety by reference.

Embodiments of the present disclosure relate to a chemical mechanical polishing apparatus.

A chemical mechanical polishing (CMP) apparatus is used in a polishing process to planarize a surface of a semiconductor wafer.

During the polishing process, an excessive heat may be generated in the polishing pad due to a friction between the polishing pad and the wafer, or between the polishing pad and the retainer ring. In this case, the hardness of the polishing pad may be reduced and the removal rate (a removal rate) in the polishing process may be reduced.

One or more embodiments provide a chemical mechanical polishing apparatus that may improve a reliability in the polishing process.

The objects of the present disclosure are not limited to the object mentioned above, and other technical objects that are not mentioned may be clearly understood to a person of an ordinary skill in the art using the following description.

According to an aspect of one or more embodiments, there is provided a chemical mechanical polishing apparatus including a polishing platen, a polishing pad on a first surface of the polishing platen, a polishing head on the polishing pad, the polishing head being configured to fix the wafer, a wafer accommodating part protruded from a first surface of the polishing head facing the first surface of the polishing pad, the wafer accommodating part having a ring shape along an edge of the first surface of the polishing head, and a cooling device including a cooling pipe on an exterior surface of the wafer accommodating part.

According to another aspect of one or more embodiments, there is provided a chemical mechanical polishing apparatus including a polishing platen, a polishing pad on the polishing platen, a polishing head on the polishing pad and configured to fix the wafer, a wafer accommodating part protruded from a first surface of the polishing head facing a first surface of the polishing pad and having a ring shape positioned along an edge of the first surface of the polishing head, and a cooling device including a cooling pipe inside or on an exterior surface of the wafer accommodating part, wherein the wafer accommodating part includes a body part and a plurality of protruding portions protruded from a second surface of the body part and arranged along a circumference direction of the body part, and at least some of the body part and the plurality of protruding portions include a thermal conductivity polymer material.

According to still another aspect of one or more embodiments, there is provided a chemical mechanical polishing apparatus including a polishing platen, a polishing pad including a lower polishing pad on a first surface of the polishing platen and an upper polishing pad on the lower polishing pad, a polishing head on the polishing pad and configured to fix the wafer, a wafer accommodating part protruded from the first surface of the polishing head facing the first surface of the polishing pad, the wafer accommodating part having a ring shape along an edge of the first surface of the polishing head, a rotation axis connected to the first surface of the polishing head and extending in a first direction vertical to the first surface of the polishing pad, and a cooling device on the polishing pad, wherein the cooling device includes a cooling pipe on an exterior surface of the wafer accommodating part, a first cooling water supply pipe on a first side with respect to the rotation axis and extending in the first direction, a first cooling water discharge pipe on a second side with respect to the rotation axis opposite to the first cooling water supply pipe, and extending in the first direction, a second cooling water supply pipe between the first cooling water supply pipe and the first cooling water discharge pipe and extending in the first direction, a second cooling water discharge pipe on a side with respect to the rotation axis opposite to the second cooling water supply pipe and extending in the first direction, a first connecting member between the first cooling water supply pipe and the cooling pipe, a second connecting member between the first cooling water discharge pipe and the cooling pipe, a third connecting member between the second cooling water supply pipe and the cooling pipe, and a fourth connecting member between the second cooling water discharge pipe and the cooling pipe.

According to one or more embodiments, by more effectively reducing the friction heat generated on the polishing pad during the polishing process, the reliability in the chemical mechanical polishing process may be improved.

The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the disclosure are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure.

In order to clearly explain the present disclosure, a portion that is not directly related to the present disclosure is omitted, and the same reference numerals are attached to the same or similar constituent elements through the entire specification.

Further, in the drawings, the sizes and thicknesses of the components are exemplarily provided for convenience of description, and the present disclosure is not limited to those shown in the drawings. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for convenience of description.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. Further, in the specification, the word “on” or “above” means positioned on or below the object portion, and does not necessarily mean positioned on the upper side of the object portion based on a gravitational direction.

In addition, unless explicitly described to the contrary, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

Further, in this specification, the phrase “on a plane” means viewing a target portion from the top, and the phrase “on a cross-section” means viewing a cross-section formed by vertically cutting a target portion from the side.

Hereinafter, a chemical mechanical polishing apparatus according to one or more embodiments will be described with reference to drawings.

is a perspective view of a chemical mechanical polishing apparatus according to one or more embodiments.is a top plan view of a chemical mechanical polishing apparatus according to one or more embodiments.is a cross-sectional view of a chemical mechanical polishing apparatus taken along a line I-I′ of.

Referring toto, the chemical mechanical polishing apparatusaccording to the one or more embodiments is an apparatus for polishing a wafer, and may include a polishing platen, a polishing padattached to the upper surface of the polishing platen, a wafer carrierpositioned on the polishing pad, and cooling devicepositioned above the polishing pad. The wafer carriermay include a polishing headand a wafer accommodating partpositioned on one surface of the polishing head.

The chemical mechanical polishing apparatusperforms a mechanical polishing while the wafermounted on the bottom of the polishing headis contact with the polishing pad, and a chemical polishing is performed through a chemical reaction by a slurry supplied from the slurry supplier.

The polishing platenmay apply a rotation energy to the polishing padso that it is rotatable in a certain direction. For example, the polishing padmay be placed (or attached) on the polishing platenand be rotated by the driving of the polishing platen.

The polishing paduniformly planarizes the surface of the waferand may perform the mechanical polishing. The polishing padmay be positioned on the polishing platenand rotated by the driving of the polishing platen. Referring toto, the polishing padis shown as consisting of one pad, but is not limited thereto. For example, the polishing padmay have a structure in which two or more pads are stacked in an upward direction (opposite to a first direction DR) and a downward direction (first direction DR).

The wafer carriermay include a polishing headpositioned on the polishing pad, and a wafer accommodating partpositioned along the edge of one surface facing the upper surface of the polishing pad. The polishing headmay fix the wafer. For example, the wafermay be adsorbed to the lower surface of polishing head. For example, the wafermay be adsorbed to the lower surface of the polishing headby at least one inhale pipe that passes through a rotation axis, which will be described later, and the interior of the polishing headand is exposed to the lower surface of the polishing head. As the polishing headrotates, the waferadsorbed on the polishing headmay rotate along with the polishing headin a clockwise direction or a counterclockwise direction. In one or more embodiments, the polishing headmay rotate in the clockwise direction, or the counterclockwise direction while being tilted in one direction.

The chemical mechanical polishing apparatusaccording to the one or more embodiments may further include the rotation axisconnected to the upper surface of the polishing head. One end of the rotation axismay be connected to the central axis of the polishing head. The rotation axismay be extended in the first direction DR. The polishing headmay be rotated in the clockwise direction or the counterclockwise direction around the rotation axis.

The polishing headmay press the polishing surface of the waferonto the polishing pad. For example, referring toto, the polishing headmay press the waferin the first direction DR. The polishing headmay further include a thin elasticity membrane positioned on one surface facing the upper surface of the polishing pad. The wafermay be rotated along with the polishing headwhile the polishing surface is pressed toward the upper surface of the polishing pad, and thus the polishing surface of the wafercan be polished.

The wafer accommodating partmay prevent the waferfrom leaving to the outside of the wafer carrierduring the polishing process. The wafer accommodating partmay be protruded from one surface of the polishing headin a downward direction. For example, the wafer accommodating partmay be protruded in the downward direction DRfrom one surface of the polishing headfacing the upper surface of the polishing pad. The wafer accommodating partmay have a ring shape. For example, the wafer accommodating partmay have the ring shape positioned along the edge of one surface of the polishing headfacing the upper surface of the polishing pad. Referring to, although the wafer accommodating partis shown to be spaced apart from the upper surface of the polishing pad, at least a portion of the wafer accommodating partmay be in contact with the polishing padduring the polishing process. The wafer accommodating partmay be fixed to the lower surface of the polishing headand rotate in the clockwise direction or the counterclockwise direction together with the polishing head.

In one or more embodiments, the wafer accommodating partmay include a polymer material. For example, the wafer accommodating partmay include synthetic resin materials such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polyimide PI ( ), etc. In one or more embodiments, the wafer accommodating partmay include a thermal conductivity polymer material in at least some regions. For example, the wafer accommodating partmay include a thermal conductivity polymer material in some regions adjacent to the upper surface of the polishing pad. For example, wafer accommodating partmay include at least one of carbon nano tube (CNT) or aluminum nitride (AlN). The specific details regarding this will be described later.

The chemical mechanical polishing apparatusaccording to the one or more embodiments may further include a cooling devicepositioned on the polishing pad. The cooling devicemay be configured to cool at least some regions of the chemical mechanical polishing apparatus. For example, the cooling devicemay be configured to cool the region where heat is generated by the friction during the polishing process of the chemical mechanical polishing apparatus.

Referring toto, the cooling deviceaccording to the one or more embodiments may include a cooling pipepositioned on the exterior surface of the wafer accommodating part. The cooling pipemay also be positioned on the exterior surface of the polishing head. The cooling pipemay be positioned along the outer circumference surface of the polishing headand the wafer accommodating part. The cooling pipemay be spaced apart from the outer circumference surface of the polishing headand the wafer accommodating partby a predetermined distance. The cooling pipemay cover at least some region of the outer circumference surface of the polishing head. The cooling pipemay cover at least some region of the outer circumference surface of the wafer accommodating part. The cooling pipemay be positioned on the polishing pad. The cooling pipemay be spaced apart from the polishing padin the thickness direction. The cooling pipemay be spaced apart from the upper surface of the polishing padalong the first direction DR. The cooling pipemay not be in contact with the polishing pad. In one or more embodiments, the cooling pipemay not move during the polishing process. For example, even if the polishing headrotates during the polishing process, the cooling pipemay be fixed without moving.

In one or more embodiments, the cooling pipemay include a material with excellent thermal conductivity. For example, the cooling pipemay include metal materials such as copper (Cu) and aluminum (Al).

The cooling deviceaccording to the one or more embodiments may include a cooling water supply pipefor supplying a cooling water to the cooling pipe, a cooling water discharge pipefor discharging the used cooling water, and connecting membersconnecting the cooling water supply pipeand the cooling pipeand provided between the water supply pipeand the cooling pipe, or the cooling water discharge pipeand the cooling pipe. The cooling water may flow inside the cooling pipe. The used cooling water may mean a cooling water that has circulated inside the cooling pipe at least once.

The cooling water supply pipemay be extended in the first direction DR. The cooling water supply pipemay be positioned on one side of the rotation axis. The cooling water supply pipemay be positioned adjacent to the sidewall of the rotation axis. Referring toto, some regions of the side of the cooling water supply pipeare shown as being in contact with the sidewall of the rotation axis, but embodiments are not limited thereto, and the cooling water supply pipemay be spaced apart from the rotation axisin the horizontal direction. The cooling water flowing in from the outside may flow to the cooling water supply pipe. The cooling water flowing into the cooling water supply pipemay flow into the cooling pipethrough the connecting member.

The cooling deviceaccording to the one or more embodiments may include a plurality of cooling water supply pipes. For example, referring to, the cooling devicemay include two cooling water supply pipesandHowever, the number of the cooling water supply pipesincluded in the cooling deviceis not limited thereto. For example, the cooling devicemay include three or more cooling water supply pipes.

The cooling water discharge pipemay be extended in the first direction DR. The cooling water discharge pipemay be positioned on the other side of the rotation axis. The cooling water discharge pipemay be positioned on the opposite side of the cooling water discharge pipewith the rotation axisin between. The cooling water discharge pipemay be positioned adjacent to the sidewall of the rotation axis. Referring toto, some regions of the side surface of the cooling water discharge pipeare shown as being in contact with the sidewall of the rotation axis, but embodiments are not limited thereto, and the cooling water discharge pipemay be spaced apart from the rotation axisin the horizontal direction. The used cooling water inflowing from the cooling pipemay flow to the cooling water discharge pipe. The cooling water that flows into the cooling water discharge pipemay be discharged to the outside.

The cooling deviceaccording to the one or more embodiments may include a plurality of cooling water discharge pipes. For example, referring to, the cooling devicemay include two cooling water discharge pipesandHowever, the number of the cooling water discharge pipesincluded in the cooling deviceis not limited thereto. For example, the cooling devicemay include three or more cooling water discharge pipes.

The connecting membersmay connect between the cooling pipeand the cooling water supply pipe, or the cooling pipeand the cooling water discharge pipe. When the chemical mechanical polishing apparatusincludes the plurality of cooling water supply pipes, the plurality of connecting membersmay connect the cooling pipeand the plurality of cooling water supply pipes, respectively. Referring toto, the first connecting membermay connect the first cooling water supply pipeand the cooling pipe, and the second connecting membermay connect the second cooling water supply pipeand the cooling pipe. The third connecting membermay connect the first cooling water discharge pipeand the cooling pipe, and the fourth connecting membermay connect the second cooling water supply pipeand the cooling pipe. The cooling water flowing in from the outside into the first and second cooling water supply pipesandmay flow into the cooling pipethrough the first connecting memberand the second connecting member, respectively. The cooling water circulating through the cooling pipemay flow into the first and second cooling water discharge pipesandrespectively, through the third connecting memberand the fourth connecting memberand then be discharged to the outside.

Each connecting membermay have a shape substantially similar to a letter ‘L’ of an alphabet turned upside down. Each end of the plurality of connecting members,,, andmay be connected to one of the first and second cooling water supply pipesandand the third and fourth cooling water supply pipesandand the other end thereof may be connected to the cooling pipe. In the one or more embodiments, the connecting membersmay cover at least a partial region of the upper surface of the polishing headand at least a partial region of the side surface of the polishing head, respectively. In the one or more embodiments, the connecting membersmay be spaced apart from the upper surface and side surface of the polishing head. While the polishing headis running, the first and second cooling water supply pipesandthe third and fourth cooling water supply pipesandand the connecting membermay not move.

The chemical mechanical polishing apparatusaccording to the one or more embodiments may further include a conditionerand a slurry supplier positioned on the polishing pad.

The conditionermay be a member that conditions the surface of the polishing pad. For example, the conditionermay maintain the surface roughness of the polishing padin an optimal state by polishing the surface of the polishing pad. While polishing the waferwith the wafer carrieror stopping the polishing of the wafer, the conditionermay restore or maintain the surface roughness of the polishing padby polishing the polishing pad. In one or more embodiments, the conditionermay be constructed by fixing polishing particles, for example, artificial diamond particles, using a nickel (Ni) adhesive layer on a circular disk made of a metal. In one or more embodiments, the conditionermay rotate in a certain direction. For example, the conditionermay rotate in the same direction as the polishing platenand the wafer carrierand may control the roughness of the polishing pad.

The slurry suppliermay be a member that supplies a slurry to the polishing pad. The slurry supplieris positioned above the polishing pad, and supplies the slurry to the polishing pad, so that the slurry is transferred to the waferthrough the micropores formed in the polishing pad, thereby performing not only the mechanical polishing of the waferdepending on the rotation of the wafer carrier, but also the chemical polishing by the slurry simultaneously.

During the polishing process, the wafer accommodating partmay be fixed to the polishing head, rotated with the polishing head, and pressed on the upper surface of the polishing pad. In this case, a friction heat may occur in the region where the polishing padand the wafer accommodating partcome into contact. When the polishing padis heated excessively due to the friction heat generated in the polishing process, the hardness of the polishing padmay decrease and the polishing speed (a removal rate) may decrease. Additionally, when a material (e.g., molybdenum (Mo)) with a relatively low melting point is positioned on the polishing surface of the wafer, the material may melt due to the friction heat, and in this case, it may not be easy to accurately determine the end point of the polishing process.

According to the one or more embodiments, the polishing padmay be prevented from being excessively heated by the friction heat by installing the cooling pipein the contact region between the wafer accommodating partand the polishing pad, where the friction heat may be generated during the polishing process.

is an enlarged view of a region A in. Referring to, the polishing headaccording to the one or more embodiments may be tilted at an angle with respect to the upper surface of the polishing pad. As the polishing headis tilted with respect to the upper surface of the polishing pad, the distance between the lower surface of the polishing headand the upper surface of the polishing padmay not be constant. For example, the distance between the lower surface of the polishing headand the upper surface of the polishing padmay gradually increase or gradually decrease from one side of the polishing headto the opposite side of the polishing head. For example, the polishing headmay be tilted diagonally to the left with respect to the upper surface of the polishing pad, as shown in. Accordingly, in, the distance between the lower surface of the polishing headand the upper surface of the polishing padmay gradually increase from the left end to the right end of the polishing head.

In the one or more embodiments, the portion where the cooling water inflows into the cooling pipemay be positioned on a side of the lower surface of the polishing headthat is relatively close to the upper surface of the polishing pad, and the portion where the cooling water is discharged from the cooling pipemay be positioned on a side of the lower surface of the polishing headthat is relatively far from the upper surface of the polishing pad. The portion where the cooling water flows into the cooling pipemay be positioned on one side of the polishing head, and the portion where the cooling water is discharged from the cooling pipemay be positioned on the other side of the polishing head. At this time, the distance between one side of the polishing headand the upper surface of the polishing padmay be smaller than the distance between the other side of the polishing headand the upper surface of the polishing pad.

For example, there may be a case where the cooling deviceincludes one cooling water supply pipeand one cooling water discharge pipe. In this example, the connection portion between the other side of the connecting member of which one side is connected to the cooling water supply pipe, and the cooling pipemay be positioned outside the point of the lower surface of the polishing headwith the closest distance to the upper surface of the polishing padamong the entire region of the lower surface of the polishing head. The connection part between the other side of the connecting member of which one side is connected to the cooling water discharge pipe, and the cooling pipe, may be positioned outside the point of the greatest distance from the upper surface of the polishing padamong the entire region of the lower surface of the polishing head.

For example, as shown into, the cooling devicemay include two cooling water supply pipesand two cooling water discharge pipes. In this example, the connection portion between the first connecting memberand the cooling pipe, and the connection portion between the second connecting memberand the cooling pipemay be positioned on both sides of the point of the lower surface of the polishing headwith the closest distance to the upper surface of the polishing padamong the entire region of the lower surface of the polishing head. The connection portion between the third connecting memberand the cooling pipe, and the connection portion between the fourth connecting memberand the cooling pipemay be positioned on both sides of the point of the lower surface of the polishing headat the greatest distance from the upper surface of the polishing padamong the entire region of the lower surface of the polishing head.

For example, referring to, among the lower surface entire region of the polishing head, the first point Pmay be the point with the closest distance to the upper surface of the polishing pad. In this example, the connection portion between the first connecting memberand the cooling pipeand the connection portion between the second connecting memberand the cooling pipemay be positioned on both sides of the first point P. The distance between the connection portion between the first connecting memberand the cooling pipeand the first point P, and the distance between the connection portion between the second connecting memberand the cooling pipeand the first point Pmay be substantially the same. For example, the connection portion between the first connecting memberand the cooling pipemay be positioned outside a point approximately 45° away in the clockwise direction along the circumference of the polishing headfrom the first point P. For example, the connection portion between the second connecting memberand the cooling pipemay be positioned outside a point approximately 45° away in the counterclockwise direction along the circumference of the polishing headfrom the first point P.

For example, referring to, among the lower surface entire region of the polishing head, the second point Pmay be the point of the lower surface of the polishing headwith the greatest distance from the upper surface of the polishing pad. In this example, the connection portion between the third connecting memberand the cooling pipeand the connection portion between the fourth connecting memberand the cooling pipemay be positioned on both sides of the second point P. The distance between the connection portion between the third connecting memberand the cooling pipeand the second point P, and the distance between the connection portion between the fourth connecting memberand the cooling pipeand the second point Pmay be substantially the same. For example, the connection portion between the third connecting memberand the cooling pipemay be positioned outside a point approximately 45° away in the clockwise direction along the circumference of the polishing headfrom the second point P. For example, the connection portion between the second connecting memberand the cooling pipemay be positioned outside a point approximately 45° away in the counterclockwise direction along the circumference of the polishing headfrom the second point P.

According to the one or more embodiments, when the polishing headis driven while being tilted in one direction, the cooling water supply pipesare placed on the side where more friction heat is generated, and the cooling water discharge pipesare placed on the side where less friction heat is generated, thereby the friction heat may be cooled efficiently.

toare views to explain the chemical mechanical polishing apparatusaccording to the one or more embodiments. For example,is a top plan view of a chemical mechanical polishing apparatus according to one or more embodiments.is a cross-sectional view of the chemical mechanical polishing apparatus along line II-II′ in.is an enlarged view of the region B in. Since the chemical mechanical polishing apparatusshown intois substantially the same as the previous embodiments, the description thereof will be omitted and the differences will be mainly explained below. For the chemical mechanical polishing apparatusaccording to the one or more embodiments, the configuration of the cooling water supply pipeand the cooling water discharge pipebeing positioned inside the rotation axisand that the cooling devicerotates together with the polishing headmay be different from the previous embodiments.