Patent Application
20250058430
This application claims priority from Korean Patent Application No. 10-2023-0107853, filed on Aug. 17, 2023, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety.
The present disclosure relates to a CMP conditioning disc and a method of manufacturing the CMP conditioning disc.
In general, the planarization process using chemical mechanical polishing (CMP) is a process in which a carrier holds a wafer to be polished, and a surface plate and the carrier are moved relative to each other to perform the polishing process while slurry is fed onto a polishing pad of the surface plate.
Numerous foam pores on the surface of the polishing pad serve to contain new polishing liquid, ensuring consistent polishing efficiency and polishing uniformity over the entire wafer. However, due to the applied pressure and relative speed during polishing, the surface of the polishing pad becomes unevenly deformed over time, and the pores on the polishing pad become clogged with polishing residues, making the polishing pad unable to function properly.
To address uneven deformation of the polishing pad and clogging of pores, a CMP pad conditioner is used. The CMP pad conditioner finely polishes the surface of the polishing pad, allowing new micro pores to form on the polishing pad. A fusion type CMP pad conditioner, a type of CMP pad conditioner, generally conditions the pad during the CMP process by fixing diamonds on a shank made of stainless steel using a fusion method. In the diamond setting process for adjusting the diamond position of a conventional fusion type CMP pad conditioner, diamonds are passed through holes of a predetermined size formed in an etched mask substrate, and the diamonds are then settled onto a disc by an adhesive sprayed on a metal powder layer on the shank.
However, in the case of the conventional CMP pad conditioner, there is a problem that during the process where the powder for brazing becomes liquid and solidifies through heat treatment after the diamond setting process, the part that holds the diamonds becomes liquid, and at this time, the positions and postures of the diamonds are distorted, causing the diamonds to be arranged irregularly on the shank.
(Patent Document) Korean Patent Application Publication No. 10-2012-0058303
In view of the above, the present disclosure provides a CMP conditioning disc capable of having a plurality of diamonds uniformly arranged on a shank base and a method of manufacturing the CMP conditioning disc.
According to the embodiment of the present disclosure, effective pad conditioning and low diamond wear can be achieved by uniformly arranging a plurality of diamonds in the X, Y, and Z directions on the shank base during the brazing process.
In addition, according to the embodiment of the present disclosure, it is possible to improve the pad cut rate (PCR) and extend the life of the CMP conditioning disc by arranging a plurality of diamonds at uniform intervals and uniform heights on the shank base through two forming processes.
In accordance with one aspect of the present disclosure, there is provided a method of manufacturing a CMP conditioning disc including: a primary forming layer forming step of forming a primary forming layer on an outer surface of a shank base and arranging a plurality of diamonds on the primary forming layer; and a secondary forming layer forming step of forming a secondary forming layer on an upper surface of the primary forming layer and exposing at least a portion of the diamonds in the secondary forming layer.
Further, in the method of manufacturing a CMP conditioning disc, the primary forming layer forming step involves forming the primary forming layer through a brazing process or sintering process, and the secondary forming layer forming step involves forming the secondary forming layer through a brazing process.
Further, in the method of manufacturing a CMP conditioning disc, the primary forming layer forming step includes: a primary metal powder layer forming step of providing a primary metal powder layer on the outer surface of the shank base and pre-sintering the primary metal powder layer; an adhesive layer forming step of forming an adhesive layer on an outer surface of the primary metal powder layer; and a primary diamond fixing step of temporarily fixing the diamonds to an outer surface of the adhesive layer.
Further, in the method of manufacturing a CMP conditioning disc, the primary diamond fixing step involves temporarily holding the plurality of diamonds in a regular pattern in rows and columns on a suction pressure device, and pressing and fixing the plurality of diamonds on the primary forming layer using the suction pressure device to maintain the upright posture of the plurality of diamonds.
Further, in the method of manufacturing a CMP conditioning disc, the secondary forming layer forming step includes: a secondary metal powder layer forming step of pre-sintering a secondary metal powder layer on the outer surface of the primary forming layer to form a secondary forming layer; and a polishing step of dry polishing the secondary forming layer to cover all of the diamonds or to expose at least a portion of the diamonds.
Further, in the method of manufacturing a CMP conditioning disc, the secondary forming layer forming step further includes: a secondary diamond fixing step of completely fixing the diamonds in the secondary forming layer through shrinkage of the dry polished secondary forming layer.
In accordance with another aspect of the present disclosure, there is provided a CMP conditioning disc including: a shank base; a primary forming layer formed on an outer surface of the shank base; a secondary forming layer formed on an outer surface of the primary forming layer; and a plurality of diamonds arranged in the primary forming layer and the secondary forming layer, at least a portion of the diamonds being exposed from the secondary forming layer.
Further, in the CMP conditioning disc, the primary forming layer is formed at a melting point that is the same as, lower than, or higher than that of the secondary forming layer.
Further, in the CMP conditioning disc, a thickness between the outer surface of the primary forming layer and an outer surface of the secondary forming layer is larger than a thickness between the outer surface of the primary forming layer and the outer surface of the shank base.
Further, the CMP conditioning disc manufactured by the methods of manufacturing a CMP conditioning disc.
Hereinafter, specific embodiments for implementing the technical ideas of the present disclosure will be described in detail with reference to the drawings.
In addition, in describing the present disclosure, when it is determined that a detailed description of the relevant known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted.
Further, when a component is mentioned to be “coupled to”, “supported by”, “connected to”, “supplied to”, “transferred to”, and “in contact with” another component, it should be understood that it may be directly coupled to, supported by, connected to, supplied to, transferred to, and in contact with another component, but there may be other components therebetween.
The terms used in the present specification are used merely to describe the specific embodiments and are not intended to limit the present disclosure. Singular expressions include the plural unless the context clearly indicates otherwise.
In addition, it should be noted in advance that in the present specification, expressions such as upper, lower, side, etc. are described based on the illustrations in the drawings, and may be expressed differently if the orientation of the subject is changed. For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically shown, and the size of each component does not entirely reflect the actual size.
Furthermore, the terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by such terms. These terms are used only to distinguish one component from another.
The meaning of “include” used in the present specification is intended to specify certain features, areas, integers, steps, operations, elements, and/or components, and is not intended to exclude the existence or the addition of other specific features, areas, integers, steps, operations, elements, components, and/or groups.
Hereinafter, the specific configuration of a CMP conditioning disc and a method of manufacturing the CMP conditioning disc according to the present disclosure will be described with reference to the drawings.
Referring to
Specifically, the shank base 100 may be a backing plate of the CMP conditioning disc 10. The primary forming layer 200 may be formed on an outer surface (top surface) of the shank base 100. Since the shank base 100 corresponds to a typical shank used in a CMP conditioning disc, detailed description thereof will be omitted.
The primary forming layer 200 may be a fixing layer for primarily fixing the plurality of diamonds 400 to the outer surface of the shank base 100. As an example, the primary forming layer 200 may be a brazed layer formed on the outer surface of the shank base 100 through a brazing process (first brazing process). In the present embodiment, the primary forming layer 200 is described as a brazed layer, but it is not limited thereto, and the primary forming layer 200 may be a sintered layer formed on the outer surface of the shank base 100 through a sintering process. In the primary forming layer 200, the plurality of diamonds 400 may be arranged in a regular pattern forming rows and columns and may be primarily fixed (temporarily fixed).
The primary forming layer 200 before heat treatment may include a primary metal powder layer 210 and an adhesive layer 220. The adhesive layer 220 may be an adhesive layer for primarily fixing (temporarily fixing) the diamonds 400 to the primary metal powder layer 210. The plurality of diamonds 400 may be regularly arranged and temporarily fixed to the primary metal powder layer 210 on which the adhesive layer 220 is applied. The primary metal powder layer 210 may be applied to the outer surface of the shank base 100 and preliminary sintered. The thickness of the primary forming layer may vary depending on an average size of the diamonds used. Generally, #60, #80, #100, and #120 diamonds are mainly used in the CMP pad conditioner. For example, when using #80 diamond, which has a diameter range of 151 μm to 197 μm and an average diameter of about 170 μm, the thickness of the primary forming layer 200 may be 20 μm to 100 μm before brazing (pre-fusion), and may be 14 μm to 70 μm after being brazed (post-fusion). The thickness of the forming layer may vary proportionally depending on the average size of the diamonds.
A thickness L2 between the outer surface of the primary forming layer 200 and the outer surface of the secondary forming layer 300 may be larger than a thickness L1 between the outer surface of the primary forming layer 200 and the outer surface of the shank base 100. If the thickness L2 between the outer surface of the primary forming layer 200 and the outer surface of the secondary forming layer is larger than the thickness L1 from the outer surface of the primary forming layer 200 to the outer surface of the shank base 100, the lower center of the diamond 400 is completely fixed by the primary forming layer 200, so that when the diamonds 400 are laid in and fixed by the secondary forming layer 300, the arrangement of the diamonds 400 can be stably maintained by the primary forming layer 200 and the secondary forming layer 300.
In the case of the brazing process, the melting point of the primary forming layer 200 may be the same as the melting point of the secondary forming layer 300 or may be higher than the melting point of the secondary forming layer 300. If the melting point of the primary forming layer 200 is higher than the melting point of the secondary forming layer 300, the primary forming layer 200 may be heat treated at a higher temperature than the secondary forming layer 300. In particular, if the melting point of the primary forming layer 200 is higher than the melting point of the secondary forming layer 300, the primary forming layer 200 may further inhibit the positional shift of the diamonds 400 during the brazing process for the secondary forming layer 300. When the components of the primary forming layer 200 are composed of components with a higher melting point than the components of the secondary forming layer 300, during the brazing process for the secondary forming layer 300, the primary forming layer 200 may have high viscosity or may exist in a sintered state (containing a solid phase) even if the secondary forming layer 300 is all liquefied. As an example, the brazing temperature for forming the primary forming layer 200 may be 900° C. to 1300° C., and the brazing pressure may be 10×10−3 Pa to 10×10−2 Pa. Meanwhile, when the primary forming layer is formed through the sintering process, the heat treatment temperature of the primary forming layer 200 may be different from the heat treatment temperature of the secondary forming layer 300.
The secondary forming layer 300 may be a fixing layer for secondarily fixing the plurality of diamonds 400 to the outer surface of the shank base 100. For example, the secondary forming layer 300 may be a brazed layer formed on the outer surface of the primary forming layer 200 through a brazing process (second brazing process). The secondary forming layer 300 may be a secondary metal powder layer for completely fixing the diamonds 400. The secondary metal powder layer may have the same component as the primary metal powder layer 210 of the primary forming layer 200. In the present embodiment, the secondary metal powder layer has been described as having the same component as the primary metal powder layer 210 of the primary forming layer 200, but the present disclosure is not limited thereto, and the component of the secondary metal powder layer may be different from the component of the primary metal powder layer 210. If the components of the secondary metal powder layer and the primary metal powder layer 210 are different from each other, the melting points of the primary forming layer 200 and the secondary forming layer 300 may be controlled differently from each other.
The secondary forming layer 300 may undergo a heat treatment process in which it is heated to a preset temperature range. In a state where the plurality of diamonds 400 are temporarily fixed by the primary forming layer 200, the plurality of diamonds 400 may be completely fixed in a regular shape forming rows and columns in the secondary forming layer 300. For example, when using #80 diamond particles having an average size of 170 μm, the thickness of the secondary forming layer 300 may be 100 μm to 250 μm before being brazed (pre-fusion), and may be 70 μm to 175 μm after being brazed (post-fusion).
The diamonds 400 may be provided in multiple numbers arranged in a regular pattern in the primary forming layer 200 and the secondary forming layer 300. At least a portion of the diamonds 400 may be exposed from the secondary forming layer 300. While the primary forming layer 200 is in a pre-sintered state, the posture (orientation) of the diamonds 400 may be adjusted to an upright state by a separate suction pressing device (not shown). As a matter of course, the position and posture of some of the diamonds 400 may shift during the sequential heat treatment processes of the primary forming layer 200 and the secondary forming layer 300, but the shift of the position and posture of the diamonds 400 can be minimized by two processes (for example, the brazing process) for forming the primary forming layer 200 and the secondary forming layer 300.
At least a portion of the diamond 400 may be a polishing part 400b located at a top of a long axis. The diamond 400 may be divided into a body part 400a laid in the primary forming layer 200 and the secondary forming layer 300, and a polishing part 400b protruding outward from the secondary forming layer 300. In the present embodiment, an imaginary line connecting two vertices the furthest apart from each other while facing each other among a plurality of vertices of the diamond 400 may be defined as an ‘axis’, and the longest axis among a plurality of ‘axes’ may be defined as a ‘long axis’.
The polishing part 400b of the diamond 400 may be positioned at the same height as the polishing part 400b of another diamond 400 as much as possible. In the present embodiment, among the plurality of diamonds 400, the proportion of diamonds 400 whose polishing parts 400b have a height difference within a range of 50 μm may be 80% or more of the total number of diamonds 400, but the present disclosure is not limited thereto. Under optimal conditions, the proportion of diamonds 400 whose polishing parts 400b have the height difference within the range of 50 μm may approach 100% of the total number of diamonds 400.
The diamonds 400 may be positioned in the primary forming layer 200 and the secondary forming layer 300 in an upright posture extending downward from the top of the long axis. For example, the diamonds 400 may be positioned in the primary forming layer 200 and the secondary forming layer 300 at an angle (for example, an angle greater than 50° and less than) 90° with respect to the shank base 100. When the diamond 400 is upright with respect to the shank base 100, the lower vertex of the long axis of the diamond 400 may be in point or line contact with the surface of the shank base 100 or may be spaced apart from the surface of the shank base 100 by a predetermined distance. As the long axis of the diamond 400 approaches 90° with respect to the shank base 100, the diamond 400 makes point and line contact with the polishing pad, so the polishing performance of the diamond 400 can be significantly increased.
Referring to
When the wetting angle θ exceeds 90°, since the vertical component of the lateral force FL is upward, the diamond 400 may receive a greater buoyancy and float further, and when the wetting angle θ is less than 90°, the direction of the vertical component of the lateral force FL may change to the lateral downward direction, so that the diamond 400 may receive a downward force. When the wetting angle θ is greater than 90°, the diamond 400 may be separated from the shank base 100 due to the buoyancy, which may cause the diamond 400 to shift its position, and the secondary forming layer 300 may not properly support the diamond 400, which increases the risk of the diamond 400 falling off, and a chip pocket for discharging debris generated during polishing process may not be formed in the bonding layer, hindering proper debris discharge and significantly reducing the polishing performance.
The diamond 400 can finely polish the polishing pad P through the polishing part 400b protruding from the secondary forming layer 300. In the present embodiment, since the polishing parts 400b of a plurality of diamonds 400 protrude from the secondary forming layer 300 at uniform intervals and uniform heights, the polishing pad P can be effectively polished.
On the other hand, in the case of a conventional CMP conditioning disc 1, polishing parts 1-3b protruding from a brazed layer 1-2 in a body portion 1-3a are arranged at irregular intervals and uneven heights in the brazed layer 1-2 of a shank 1-1, so that the durability and pad polishing characteristics (PCR: pad cut rate), etc. may be lower than those of the CMP conditioning disc 10 of the present disclosure. As a result of the test, it has been confirmed that the CMP conditioning disc 10 of the present disclosure provides an effect of extending the lifespan by 30% or more than the conventional CMP conditioning disc 1.
Hereinafter, a method of manufacturing a CMP conditioning disc according to one embodiment of the present disclosure will be described.
Referring to
In the primary forming layer forming step S100, a primary forming layer 200 may be formed on an outer surface of a shank base 100, and a plurality of diamonds 400 may be fixed to the primary forming layer 200. In the primary forming layer forming step S100, the primary forming layer 200 may be formed through a fusion process. In the present embodiment, the primary forming layer forming step S100 includes a brazing process, but the present disclosure is not limited thereto, and the primary forming layer forming step S100 may also include a sintering process.
The primary forming layer forming step S100 may include a primary metal powder layer forming step S110, an adhesive layer forming step S120, and a primary diamond fixing step S130. In the primary metal powder layer forming step S110, primary metal powder may be provided on the outer surface of the shank base 100 and brazed. The primary metal powder layer 210 may be applied to the outer surface of the shank base 100 in a slurry form and pre-sintered. For example, in the brazing process of the primary metal powder layer 210, when the primary metal powder is applied to the outer surface of the shank base 100 in powder form, the primary metal powder may be pre-sintered to form the primary metal powder layer 210.
In the primary metal powder layer forming step S110, the primary forming layer 200 may be provided as the primary metal powder layer 210 in the slurry form. When the primary metal powder layer 210 is brazed to a thin thickness during the brazing process for the primary metal powder layer 210, the primary metal powder layer 210 can shrink and fix the diamonds 400 while minimizing the positional shift of the diamonds 400. The primary metal powder layer 210 may be pre-sintered at a temperature of 600° C. to 1000° C. In this case, there is almost no change in the thickness of the primary metal powder layer 210.
In the primary metal powder layer forming step S110, the thickness of the primary metal powder layer may be adjusted through polishing after pre-sintering the primary metal powder layer 210. When the thickness of the primary metal powder layer is reduced, when the diamond 400 is separated from the outer surface of the shank base 100, the lower part of the diamond 400 can be positioned as close as possible to the outer surface of the shank base 100.
In the adhesive layer forming step S120, an adhesive layer 220 may be formed on an outer surface of the primary metal powder layer 210. The adhesive layer 220) may be formed by applying (spraying) a slurry-type adhesive to the outer surface of the primary metal powder layer 210. In the primary diamond fixing step S130, a plurality of diamonds 400 may be fixed to the primary forming layer 200. For example, the plurality of diamonds 400 may be pressed into the pre-sintered layer of the primary metal powder layer 210 and fixed by the adhesive layer 220.
In the primary diamond fixing step S130, the plurality of diamonds 400 may be primarily fixed (temporarily fixed) in a regular pattern of rows and columns in an upright state in the primary forming layer 200. The orientation of the plurality of diamonds 400 may be controlled by a separate suction pressing device. For example, the plurality of diamonds 400 may be arranged at an upright angle with respect to the primary forming layer 200 by the suction pressing device. The suction pressing device temporarily holds the plurality of diamonds 400 in the regular pattern of rows and columns, presses the plurality of diamonds 400 onto the primary forming layer 200, and then releases the holding of the diamonds 400, thereby primarily fixing the plurality of diamonds 400 on the primary forming layer 200. If the orientation control for the plurality of diamonds 400 is not required, the plurality of diamonds 400 may be fixed to the surface of the primary metal powder layer 210 or the pre-sintered layer using an adhesive. In this case, since the thickness of the primary forming layer 200 is thin, shift of the position and orientation of the diamonds 400 can be minimized.
In the primary diamond fixing step S130, the plurality of diamonds 400 may be heat-treated while fixed to the primary forming layer 200. In this case, the heat treatment temperature may be 1000° C. to 1300° C. The heat treatment temperature may be the same as or different from the heat treatment temperature of the secondary forming layer 300. In this case, the thickness of the primary forming layer 200 may be reduced by about 30% (thickness of the primary forming layer after brazing).
In a state in which the primary diamond fixing step S130 is completed, the diamond may be fixed in contact with or close to the shank base 100 with minimal shift in position or orientation. Even if the density of the primary forming layer 200 is about twice as high as that of the diamonds, since the thickness of the primary forming layer after the heat treatment is less than half the size of the diamond, the positional shift of the diamond can be minimized.
In the secondary forming layer forming step S200, the secondary forming layer 300 may be formed on the outer surface of the primary forming layer 200, and an environment for at least a portion of the diamond 400 to be exposed from the secondary forming layer 300 may be provided. In the secondary forming layer forming step S200, the secondary forming layer 300 may be formed through a brazing process. The secondary forming layer forming step S200 may include a secondary metal powder layer forming step S210, a polishing step S220, and a secondary diamond fixing step S230.
In the secondary metal powder layer forming step S210, the secondary forming layer 300 may be brazed by providing a secondary metal powder layer on the outer surface of the primary forming layer 200. During the brazing process of the secondary forming layer 300, when the secondary metal powder is applied to the outer surface of the primary forming layer 200, the secondary metal powder may be pre-sintered to form the secondary forming layer 300.
In the polishing step S220, the secondary forming layer 300 is dry polished, so that at least a portion of the diamond 400 may be exposed from the secondary forming layer 300. In the present embodiment, the pressure for dry polishing the secondary forming layer 300 may be 0 psi to 3 psi, and the rotation speed for polishing may be 30 rpm to 130 rpm.
In the secondary diamond fixing step S230, a heat treatment process for shrinking the dry-polished secondary forming layer 300 may be provided. The plurality of diamonds 400 may be finally completely fixed in the secondary forming layer 300 through the heat treatment process. The heat treatment temperature may be 1000° C. to 1300° C. During the heat treatment process, the thickness of the secondary forming layer 300 may be reduced, so that the diamonds may relatively protrude. In the state in which the primary diamond fixing step S130 of the primary forming layer 200 is completed, the diamond is fixed in contact with or close to the shank base 100, so that even if remelting occurs in some areas of the primary forming layer 200, no further shrinkage occurs in the primary forming layer 200, thereby suppressing the positional shift of the diamond 400. As a result, even when the secondary forming layer 300 melts and shrinks in thickness due to brazing, the shift of the diamond can be minimized.
As described above, in the present disclosure, through the primary and secondary forming layer formation steps, the primary forming layer is already in a shrunken state and does not undergo volume (thickness) change during the secondary heat treatment, thereby suppressing the shift of the diamonds. In particular, by making the components of the primary forming layer and the secondary forming layer different, if the viscosity is high even in a solid-state, liquid sintered state, or 100% liquefied state in the secondary forming process, the suppression of diamond shift can be more effective.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0107853 | Aug 2023 | KR | national |
