CN114425743A - A polishing pad and chemical mechanical polishing equipment - Google Patents

Abstract

The invention discloses a polishing pad and chemical mechanical polishing equipment, and relates to the technical field of chemical mechanical polishing. In the case of prolonging the service time of the polishing pad, the frequency of replacing the polishing pad is reduced, and the polishing efficiency is improved. The polishing pad includes a polishing layer. The polishing layer includes at least two polishing portions with different heights. The present invention also provides a chemical mechanical polishing device applied to the above-mentioned polishing pad.

Description

A kind of polishing pad and chemical mechanical polishing equipment

technical field

The invention relates to the technical field of chemical mechanical polishing, in particular to a polishing pad and chemical mechanical polishing equipment.

Background technique

Chemical mechanical polishing (Chemical Mechanical Polishing, abbreviated as CMP) is a global surface planarization technology.

The polishing pad is one of the important components to realize chemical mechanical polishing. The polishing pad is worn out during use. Continuing to use a worn pad will reduce polishing efficiency and polishing quality. However, if the polishing pad is replaced frequently, the polishing efficiency will also be reduced because the chemical mechanical polishing operation needs to be suspended for the replacement of the polishing pad.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a polishing pad and chemical mechanical polishing equipment, which can reduce the frequency of replacing the polishing pad and improve the polishing efficiency under the condition of prolonging the service time of the polishing pad.

In order to achieve the above objects, the present invention provides a polishing pad, which includes a polishing layer. The polishing layer includes at least two polishing portions with different heights.

Compared with the prior art, the polishing layer included in the polishing pad provided by the present invention has at least two polishing parts with different heights, that is, the different polishing parts have a height difference, and the height difference is greater than 0. When the polishing pad provided by the present invention is applied to wafer polishing, the surface of the wafer to be polished first contacts the higher polishing portion, and does not contact other polishing portions below the higher polishing portion. At this time, only the higher polishing portion participates in the polishing of the wafer, and other polishing portions located below the higher polishing portion do not participate in the polishing of the wafer. After the higher polished portion participating in the wafer polishing is worn as the polishing progresses, the height of the higher polished portion decreases. When the height of the higher polishing portion is reduced to be consistent with the height of the polishing portion with the smallest height difference, the other polishing portion located below the higher polishing portion is in contact with the surface of the wafer. Another polishing part participates in polishing of the wafer. Based on this, after a polishing part included in the polishing pad provided by the present invention is worn out, another polishing part with the smallest height difference can continue to participate in the polishing of the wafer. polishing pad. Therefore, the replacement frequency of the polishing pad can be reduced, the polishing time of the polishing pad can be prolonged, and the polishing efficiency can be improved.

The present invention also provides a chemical mechanical polishing device, which is used for polishing wafers. Chemical mechanical polishing equipment includes a turntable, a grinding head, a polishing liquid delivery device and a polishing pad. The polishing pad is arranged on the bearing surface of the turntable. The grinding head is used to carry the wafer. The polishing liquid conveying device is used for conveying the polishing liquid to the polishing pad. The polishing pad is the polishing pad provided by any implementation manner of the present invention.

Compared with the prior art, the beneficial effects of the chemical mechanical polishing equipment provided by the present invention are the same as the beneficial effects of the polishing pad of the above-mentioned technical solution, which will not be repeated here.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

Fig. 1 is the structural representation of chemical mechanical polishing equipment provided by the related art;

2 is a schematic structural diagram of a polishing pad provided by an embodiment of the present invention;

3 is a schematic top view of a polishing pad provided by an embodiment of the present invention;

4 is a schematic structural diagram of a polishing portion of a polishing pad provided by an embodiment of the present invention;

5 is another schematic structural diagram of the polishing pad provided by an embodiment of the present invention;

6 is a schematic structural diagram of a polishing portion of a polishing pad provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a chemical mechanical polishing apparatus provided by an embodiment of the present invention.

in:

10-turntable, 11-grinding assembly, 12-polishing liquid conveying device;

13-polishing pad, 14-wafer, 15-polishing liquid;

2-polishing pad, 20-polishing layer, 200-polishing part;

200-1 - higher polished section, 200-2 lower polished section;

2000-polishing column, 21-adhesion layer, 200a-first polishing part;

200b-the second polishing part, 200c-the third polishing part, 2000a-the first polishing column;

2000b - the second polishing column, 2000c - the third polishing column, c1 - the first concentric circle;

c2-second concentric circle, c3-third concentric circle, cn-Nth concentric circle.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments.

Various schematic diagrams of embodiments of the invention are shown in the accompanying drawings, which are not drawn to scale. Therein, some details have been exaggerated and some details may have been omitted for the purpose of clarity. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships are only exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art should Regions/layers with different shapes, sizes, relative positions can be additionally designed as desired.

Hereinafter, the terms "first", "second", etc. are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of this application, unless stated otherwise, "plurality" means two or more.

In addition, in the present invention, the orientation terms such as "upper" and "lower" are defined relative to the orientation in which the components in the drawings are schematically placed. It should be understood that these directional terms are relative concepts, and they are used for relative Description and clarification, which may vary according to the orientation in which the components are placed in the figures.

In the present invention, unless otherwise expressly specified and limited, the term "connection" should be understood in a broad sense, for example, "connection" may be a fixed connection, a detachable connection, or an integrated; it may be directly connected, or It can be indirectly connected through an intermediary.

Chemical mechanical polishing is a surface planarization technology that utilizes chemical mechanical polishing equipment to achieve the purpose of flattening the wafer surface. FIG. 1 shows a schematic structural diagram of a chemical mechanical polishing apparatus provided by the related art. As shown in FIG. 1 , the chemical mechanical polishing apparatus may include a turntable 10 , a grinding assembly 11 , a polishing liquid delivery device 12 and a polishing pad 13 .

The above-mentioned polishing pad 13 may be disposed on the bearing surface of the turntable 10 by means of sticking. The above-mentioned grinding assembly 11 can carry the wafer 14 by vacuum adsorption. The above-mentioned polishing liquid delivery device 12 supplies the polishing liquid 15 to the polishing pad during the planarization process.

During actual use, the grinding assembly 11 carrying the wafer 14 can be pressed against the rotating polishing pad 13 driven by the turntable 10 with a certain pressure. At this time, the polishing liquid delivery device 12 continuously supplies the polishing liquid 15 to the polishing pad 13 . The polishing liquid 15 is evenly distributed on the surface of the polishing pad 13 under the action of the centrifugal force of the polishing pad 13 . A liquid film is formed between the wafer 14 and the polishing pad 13, and the chemical components in the polishing liquid 15 react with the wafer 14 to convert insoluble substances into soluble substances. The above-mentioned soluble substances are removed from the surface of the wafer 14 by micro-mechanical friction of the particles, and flow out of the polishing pad along with the polishing liquid 15 , so as to achieve the purpose of flattening the surface of the wafer 14 .

Referring to FIG. 1 , the polishing pad 13 used in the prior art is generally a planar polishing pad. During the use of the flat polishing pad, local wear will occur. Continuing to use a partially worn flat polishing pad will not only affect the polishing quality (such as wafer flatness), but also reduce polishing efficiency. When the planar polishing pad is partially worn, the polishing operation is suspended and the polishing pad 13 is replaced, which not only increases the polishing cost due to frequent replacement of the polishing pad 13, but also further reduces the polishing efficiency.

In view of the above technical problems, embodiments of the present invention provide a polishing pad. FIG. 2 shows a schematic structural diagram of a polishing pad provided by an embodiment of the present invention. As shown in FIG. 2 , the polishing pad 2 provided in the embodiment of the present invention includes a polishing layer 20 , and the polishing layer 20 includes at least two polishing portions 200 with different heights. That is to say, different polishing parts 200 have height differences, and the height differences are greater than zero.

The above-mentioned polishing layer 20 may include opposite upper and lower surfaces. In practical applications, the upper surface of the polishing layer 20 is in contact with the wafer to achieve polishing of the wafer. The lower surface of the polishing layer 20 can be pasted on the bearing surface of the turntable of the chemical mechanical polishing apparatus by means of adhesion. Alternatively, an adhesive layer 21 is provided on the lower surface of the polishing layer 20, and the adhesive layer 21 is pasted on the bearing surface of the turntable of the chemical mechanical polishing apparatus. The adhesive layer 21 may be disposed on the lower surface of the polishing layer by means of bonding. The adhesion layer 21 and the polishing layer 20 may also be formed by integral molding to form the polishing pad 2 provided in the embodiment of the present invention.

Referring to FIG. 2 , the outline of the outer edge of the polishing layer 20 may be consistent with the outline of the outer edge of the turntable, which is not specifically limited herein. For example, when the outline of the outer edge of the turntable is circular, the outline of the outer edge of the polishing layer 20 may also be circular. When the adhesive layer 21 is further disposed under the polishing layer 20, the outer edge contour of the adhesive layer 21 may also be circular.

Referring to FIG. 2 , the material of the polishing layer 20 may be selected according to the actual situation, which is not specifically limited herein. For example, the material of the polishing layer 20 may be polyurethane or the like.

Referring to FIG. 2, the polishing layer 20 may be processed to form a plurality of polished portions 200 of varying heights. For example, when there are two polishing parts 200 , the height of one polishing part 200 is H1 , the height of the other polishing part 200 is H2 , and the difference between H1 and H2 is greater than 0.

Referring to FIG. 4 , for another example, when there are three polishing parts 200 (respectively 200a, 200b and 200c), each polishing part 200 has a corresponding height value, which may be H1, H2 and H3, respectively, where H1> H2>H3. At this time, the difference between H1 and H2 and the difference between H2 and H3 may be the same or different.

Referring to FIG. 7 , for the convenience of description, one of the two polishing parts shown in FIG. 7 is defined as a higher polishing part 200 - 1 , and the other is defined as a lower polishing part 200 - 2 . When the polishing pad 2 provided in the embodiment of the present invention is applied to the polishing of the wafer 14, the surface of the wafer 14 to be polished is first in contact with the higher polishing portion 200-1, and is located below the higher polishing portion 200-1. The lower polished portion 200-2 is not in contact. At this time, only the higher polishing part 200 - 1 participates in the polishing of the wafer 14 , and the lower polishing part 200 - 2 does not participate in the polishing of the wafer 14 . After the higher polishing portion 200-1 participating in the polishing of the wafer 14 is worn out as the polishing proceeds, the height of the higher polishing portion 200-1 decreases. When the height of the higher polishing portion 200-1 decreases to be consistent with the height of the lower polishing portion 200-2, the lower polishing portion 200-2 contacts the surface of the wafer 14. At this time, the lower polishing portion 200-2 is mainly The polishing sections 200 - 21 of the wafers 14 are involved in polishing. Based on this, after the higher polishing portion 200-1 included in the polishing pad 2 provided by the embodiment of the present invention is worn out, the lower polishing portion 200-2 can continue to participate in the polishing of the wafer 14, and at this time, there is no need to suspend the polishing operation , and replace the worn polishing pad 2. Therefore, the replacement frequency of the polishing pad 2 can be reduced, the polishing time of the polishing pad 2 can be prolonged, and the polishing efficiency can be improved.

The specific structures of the above-mentioned polishing parts 200 are various. The following will take the polishing layer 20 including three polishing parts 200 as an example to describe the structure of the polishing parts 200 in detail. It should be understood that the following descriptions are only for explanations. Not as a limitation.

3 and 4, the above-mentioned polishing layer 20 includes a first polishing portion 200a, a second polishing portion 200b and a third polishing portion 200c. The first polishing portion 200a includes a plurality of first polishing columns 2000a, the second polishing portion 200b includes a plurality of second polishing columns 2000b, and the third polishing portion 200c includes a plurality of third polishing columns 2000c.

Referring to FIG. 3 and FIG. 4 , the plurality of first polishing columns 2000a all have the same height value H1, and the top surfaces of the plurality of first polishing columns 2000a are flush. The plurality of second polishing columns 2000b all have the same height value H2, and the top surfaces of the plurality of second polishing columns 2000b are flush. The plurality of third polishing columns 2000c all have the same height value H3, and the top surfaces of the plurality of third polishing columns 2000c are flush. In the case of H1>H2>H3, the difference between H1 and H2 and the difference between H2 and H3 may or may not be equal.

Referring to FIG. 3 and FIG. 4 , in terms of the distribution form, a plurality of first polishing columns 2000 a , second polishing columns 2000 b , and third polishing columns 2000 c may constitute a polishing portion 200 distributed in an array. The outline of the outer edge of the polishing portion 200 may be round or square. The outline of the outer edge of the array is a circle as an example to illustrate the plurality of polishing columns (including the first polishing portion 200 a, the second polishing portion 200 b and the third polishing portion 200 c ) included in the polishing portion 200 (including the first polishing portion 200 a , the second polishing portion 200 b and the third polishing portion 200 c ). The specific distribution form of the column 2000a, the second polishing column 2000b and the third polishing column 2000c). It should be understood that the following examples are for illustration only, not for limitation.

Referring to FIG. 3 and FIG. 4 , in addition, the circular contours corresponding to the above arrays may be concentric circles. For the convenience of description, the concentric circles from the outside to the inside can be sequentially defined as the first concentric circle c1, the second concentric circle c2, the third concentric circle c3, ... the Nth concentric circle cn (N is a positive integer greater than 3).

Wherein, each concentric circle (including the first concentric circle c1, the second concentric circle c2, the third concentric circle c3, ... the Nth concentric circle cn) is distributed with a plurality of first polishing columns 2000a and second polishing columns 2000b and the third polishing column 2000c. The plurality of polishing columns located on the same concentric circle are sequentially distributed in the order of the first polishing column 2000a, the second polishing column 2000b and the third polishing column 2000c.

Referring to FIGS. 3 and 4 , as an example, a plurality of polishing columns distributed on the same concentric circle have spaces between them. Also, there is space between the plurality of polishing columns distributed on different concentric circles.

Referring to FIG. 3 and FIG. 4 , based on this, the existence of the above-mentioned interval can be used as a space for storing polishing liquid. Compared with the existing planar polishing pad, more polishing liquid can be stored to improve polishing efficiency and polishing quality. Moreover, with the circulation of the polishing liquid on the polishing pad 2, the above-mentioned interval can also be used as a conveying channel of the polishing liquid, and the polishing liquid that has participated in the polishing can be discharged from the polishing pad 2 in an orderly manner along the above-mentioned interval.

Referring to FIG. 3 and FIG. 4 , in the case that there are also intervals between the plurality of polishing columns located in the first concentric circles and between the plurality of polishing columns distributed on different concentric circles, the distance between adjacent polishing columns The spacing can be equal or unequal. When the distances between adjacent polishing columns are equal, the spaces formed by the distances between adjacent polishing columns can substantially accommodate the same amount of polishing liquid. At this time, the consistency of wafer polishing in different regions of the polishing layer can be improved, so as to optimize the polishing effect of the wafer.

Referring to FIGS. 3 and 4 , each polishing column may have a diameter greater than, equal to, or smaller than the spacing between adjacent polishing columns. It should be understood that the diameter of the polishing column here is a diameter in a broad sense. For example, when the polishing column is a cylindrical polishing column, the diameter of the polishing column refers to the diameter of the bottom surface or the top surface of the cylindrical polishing column. When the polishing column is a square polishing column, the diameter of the polishing column refers to the length of the long side of the bottom surface or the top surface of the square polishing column. When the polishing column is a truncated conical polishing column, the diameter of the polishing column refers to the diameter of the bottom surface of the truncated conical polishing column. When the polishing column is an inverted truncated conical polishing column, the diameter of the polishing column refers to the diameter of the top surface of the inverted truncated conical polishing column. When the polishing column is a special-shaped polishing column, the diameter of the polishing column refers to the diameter corresponding to the largest cross-section of the special-shaped polishing column. The special-shaped polishing column can be a bottom-up polishing column with different cross-sectional shapes. When the diameter of each polishing column (including the first polishing column 2000a, the second polishing column 2000b and the third polishing column 2000c) is larger than the spacing between adjacent polishing columns, the polishing layer with the same area can be as much as possible on the polishing layer. There are many distributed polishing columns, and at this time, the area of the part involved in wafer polishing is relatively large. Based on this, the polishing efficiency of the wafer can be improved.

As another example, referring to FIG. 5 and FIG. 6 , a plurality of polishing columns distributed on the same concentric circle abut against each other, and polishing columns distributed on different concentric circles may abut against each other or have an interval.

In the case of using the above technical solution, due to the height difference between the polishing columns included in different polishing parts, there is a space between the different polishing columns. When the polishing pad provided by the above technical solution is used to polish the wafer, the above-mentioned space can accommodate polishing fluid. At this time, compared with the planar polishing pad provided in the prior art, the amount of the polishing liquid contained is increased, and based on this, the polishing efficiency and polishing quality can be improved. Moreover, since the polishing columns included in different polishing parts can abut against each other, more polishing columns can be distributed on the polishing layer 200 with the same area. At this time, the area where the polishing layer 200 actually participates in polishing can be increased. Based on this, polishing efficiency can be improved.

Referring to FIG. 7 , an embodiment of the present invention further provides a chemical mechanical polishing apparatus, and the chemical mechanical polishing apparatus is used for polishing the wafer 14 . The chemical mechanical polishing apparatus includes a turntable 10 , a grinding head 11 , a polishing liquid delivery device 12 and a polishing pad 2 . The polishing pad 2 is arranged on the bearing surface of the turntable 10 . The grinding head 11 is used to carry the wafer 14 . The polishing liquid delivery device 12 is used to deliver the polishing liquid 15 to the polishing pad 2 . The polishing pad 2 is the polishing pad 2 provided in the embodiment of the present invention.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for related parts, please refer to the partial descriptions of the method embodiments.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1 . A polishing pad, characterized in that, the polishing pad comprises a polishing layer; the polishing layer comprises at least two polishing portions with different heights. 2 . The polishing pad according to claim 1 , wherein the polishing layer comprises at least three polishing parts with different heights, and the polishing parts are arranged in the order of height; the height difference between the adjacent polishing parts same or different. 3 . The polishing pad according to claim 2 , wherein each of the polishing parts comprises a plurality of polishing columns; the plurality of polishing columns in the same polishing part have the same height, and the polishing columns between different polishing parts have the same height. 4 . Different heights. 4 . The polishing pad according to claim 3 , wherein there is a space between the adjacent polishing parts, or the adjacent polishing parts abut against each other. 5 . 5 . The polishing pad according to claim 3 , wherein a plurality of the polishing columns in the same polishing portion have a space between them, or the plurality of the polishing columns in the same polishing portion abut against each other. 6 . . 6. The polishing pad according to claim 4 or 5, characterized in that there is an interval between adjacent polishing parts, and a plurality of the polishing columns of the same polishing part have an interval; The intervals between the polishing columns are the same or different. 7 . The polishing pad of claim 3 , wherein the diameter of the polishing columns is greater than the spacing between adjacent polishing columns. 8 . 8. The polishing pad according to claim 3, wherein the polishing column is a cylindrical polishing column, a square polishing column, a truncated conical polishing column, an inverted truncated conical polishing column or a special-shaped polishing column. 9 . The polishing pad according to claim 1 , wherein the polishing pad further comprises an adhesive layer, and the adhesive layer is disposed on the bottom surface of the polishing layer. 10 . 10. A chemical mechanical polishing device, characterized in that the chemical mechanical polishing device is used for polishing wafers; the chemical mechanical polishing device comprises a turntable, a grinding head, a polishing liquid conveying device and a polishing pad; the polishing pad is provided with On the bearing surface of the turntable; the grinding head is used to carry the wafer; the polishing liquid delivery device is used to deliver the polishing liquid to the polishing pad; The polishing pad is the polishing pad of any one of claims 1 to 9.

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