CN112809550B

CN112809550B - Polishing pad

Info

Publication number: CN112809550B
Application number: CN202011617011.6A
Authority: CN
Inventors: 刘敏; 黄学良; 邱瑞英; 王腾; 杨佳佳; 张季平
Original assignee: Hubei Dinglong Co ltd; Hubei Dinghui Microelectronics Materials Co ltd; Yangtze Memory Technologies Co Ltd
Current assignee: Hubei Dinglong Co ltd; Hubei Dinghui Microelectronics Materials Co ltd; Yangtze Memory Technologies Co Ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2022-04-22
Anticipated expiration: 2040-12-31
Also published as: CN112809550A

Abstract

The invention discloses a polishing pad, which comprises a grinding layer, wherein the grinding layer comprises at least two concentric circular grooves, the innermost concentric circular groove is defined as a first concentric circle, and the outermost concentric circular groove is defined as a second concentric circle; the first concentric circle and the second concentric circle define a plurality of grinding areas, the widths of the three grinding areas from the circle center to the edge of the grinding layer are W1, W2 and W3 in sequence.

Description

Polishing pad

Technical Field

The invention relates to a polishing pad, in particular to a polishing pad with a well-designed grinding layer, physical parameters of a buffer layer and a surface groove structure, which is used for chemically and mechanically polishing a ground material.

Background

In the fabrication of integrated circuits, other electronic devices, and optical materials, many processes involving polishing, thinning, or planarizing of the material are most commonly used chemical mechanical polishing. The action principle of chemical mechanical polishing is that on a fixed polishing machine, a grinding liquid acts on a polishing pad, the polishing pad is in contact with the surface of a ground material, chemical reaction can occur, meanwhile, the polishing pad and the ground material do rotary motion on the machine, mechanical action of shearing is generated, and the chemical action and the mechanical action polish the ground material together to form a desired pattern structure.

Therefore, the flow and distribution of the slurry, the distribution of the mechanical force generated by the grooves, etc. have a determining effect on the performance of the chemical mechanical polishing pad, and on the other hand, the combination of different patterns and materials has different requirements on the effects of the above factors, and the prior art has not been studied about the combination of the groove patterns and the material of the polishing pad. Many attempts have been made to provide polishing pads with excellent overall performance in terms of polishing rate, non-uniformity, defectivity, dishing and erosion.

Chinese patent publication No. CN102498549A discloses a polishing pad having a concentric groove structure with respect to the width W of the concentric grooves_GAnd a faying surface W_LThe relationship of (a) to (b) was investigated, but the polishing pad had an excessively large groove ratio, which easily caused a decrease in polishing rate.

Chinese patent publication No. CN105793962B discloses a polishing pad with an offset concentric groove pattern, which comprises a groove region and a removal region, wherein the removal region does not contain grooves, but the purpose of the removal region is to reduce the defect of the edge of the polishing pad, thereby improving the scratch of the polished substrate, and does not disclose the relationship between the specific parameters of the peripheral surface and the polishing performance, nor how to solve the problem of polishing non-uniformity.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a polishing pad comprising an abrasive layer having a hardness in the range of 50 to 67D, a density in the range of 0.66 to 0.87g/cm3, and a compressibility in the range of 0.001 to 0.06; the grinding layer is in direct contact with a ground material and comprises at least two concentric circular grooves, the innermost concentric circular groove is defined as a first concentric circle, and the outermost concentric circular groove is defined as a second concentric circle; the first concentric circle and the second concentric circle define a plurality of polishing regions, and are defined in a radial direction, wherein a distance from an innermost side of the first concentric circle to a center of the polishing layer is W1, a distance from an outermost side of the second concentric circle to an edge of the polishing layer is W3, and a radius of the polishing layer is R, wherein:

a first polishing zone having a first concentric circular inner region with a width W1;

a second polishing zone having a region between the first concentric circle and the second concentric circle, having a width W2 ═ R-W1-W3;

a third grinding zone; having a region between the second concentric circle and the edge of the polishing layer having a width W3;

the range of W2/P is 70-380, and the range of W2/R is 0.78-0.94;

the width of the concentric circular grooves of the second grinding area is Wa, the distance between the grooves is P, and the range of Wa/P is 0.05-0.35; the range of W1/R is 0.01-0.10, and the range of W3/R is 0.05-0.12;

the third grinding area further comprises third grooves, the outer side ends of the third grooves are connected with the edge of the grinding layer, the inner side ends of the third grooves are arranged in the second area, the number of the third grooves is 2 x K, K is more than or equal to 1 and less than or equal to 48, and K is an integer;

the polishing pad also comprises a buffer layer, wherein the hardness of the buffer layer ranges from 59A to 86A, and the density ranges from 0.25 g/cm to 0.4g/cm³The compressibility ranges from 0.02 to 0.12.

According to one embodiment of the present invention, the difference between the hardness of the polishing layer and the hardness of the buffer layer is in the range of 29 to 45.5D, and the difference between the densities of the polishing layer and the buffer layer is in the range of 0.32 to 0.46g/cm³The absolute value of the difference in compressibility ranges from 0.025 to 0.089.

According to an embodiment of the present invention, an inner side end of the third trench is connected to an nth concentric circular trench from outside to inside of the second region, and n is an integer of 1 to 12.

According to an embodiment of the present invention, a total area Sb of the third grooves and a total area Sa of the second region concentric circular grooves satisfy: Sb/Sa is more than or equal to 0.01 and less than or equal to 0.4.

According to one embodiment of the present invention, the third trench has a length Lb, W3 & ltLb & lt 2.7W3, and a width Wb, wherein Wb is in a range of 0.5-6 mm.

According to one embodiment of the invention, W3/R ranges from 0.06 to 0.10.

According to one embodiment of the present invention, the abrasive layer has a hardness ranging from 54 to 64D, a density ranging from 0.67 to 0.73g/cm3, and a compressibility ranging from 0.001 to 0.025.

According to one embodiment of the present invention, the buffer layer has a hardness ranging from 67 to 77A and a density ranging from 0.27 to 0.35g/cm³The compressibility ranges from 0.05 to 0.09.

According to one embodiment of the present invention, the difference between the hardness of the polishing layer and the hardness of the buffer layer is in the range of 35 to 45D, and the difference between the densities of the polishing layer and the buffer layer is in the range of 0.35 to 0.43g/cm³。

According to an embodiment of the present invention, a total area Sb of the third grooves and a total area Sa of the second region concentric circular grooves satisfy: Sb/Sa is more than or equal to 0.01 and less than or equal to 0.2.

According to an embodiment of the present invention, the third trench is a straight line, and the length of the third trench is Lb, where Lb is W3+ (n-1) P, and n is an integer of 3 to 10; the width of the third groove is Wb, and the range of Wb is 2.5-4.5 mm.

According to one embodiment of the invention, the third grooves have a depth Db, and the concentric grooves have a depth Da, defining Vb/Va ═ (Sb × Db)/(Sa × Da), where Vb/Va ranges from 0.005 to 0.6.

According to one embodiment of the invention, the groove width Wa is in the range of 0.1 to 0.6mm, preferably 0.2 to 0.55 mm.

According to one embodiment of the present invention, the third trench is a straight line, the third trench has a length Lb, W3 Lb 2.05W 3.

According to one embodiment of the present invention, W2/P ranges from 100-380.

According to an embodiment of the present invention, a ratio of the depth Db of the third groove to the depth Da of the second region concentric circular groove, i.e., Db/Da, is in a range of 0.5 to 1.5.

According to an embodiment of the present invention, a ratio of the depth Db of the third groove to the depth Da of the second region concentric circular groove, i.e., Db/Da, is in a range of 0.8 to 1.2.

According to an embodiment of the invention, the third groove has a depth Db, and the concentric grooves have a depth Da, defining Vb/Va ═ (Sb × Db)/(Sa × Da), where Vb/Va is in the range of 0.008-0.24.

In accordance with one disclosed embodiment, the polishing layer of the polishing pad of the invention also optionally comprises an endpoint detection window, preferably the detection window is an integrity window incorporated into the polishing layer.

The above embodiments are merely specific descriptions of the technical concept of the present invention, and the present invention is not to be construed as being limited to these embodiments.

The invention has the beneficial effects that:

by designing the physical parameters of the grinding layer and the buffer layer and combining the design of different grinding areas and the sizes of grooves of the grinding layer, the polishing pad with excellent comprehensive performance is obtained, is particularly suitable for grinding oxide, has low defect degree of a polished material, gives consideration to good grinding rate and grinding uniformity, and keeps lower loss rate (cut rate).

Drawings

The above and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings, which are to be taken in a schematic view without representing the scale and dimensions of the present invention.

FIG. 1 shows a plan view of a polishing pad according to a preferred embodiment of the present invention.

FIG. 2 shows a cross-sectional view of the polishing pad of the preferred embodiment of FIG. 1 at section A-A.

Fig. 3 shows a partial enlargement of the preferred embodiment of fig. 2 within the dashed box B.

Fig. 4 shows a plan view of a polishing pad according to another preferred embodiment of the present invention.

FIG. 5 shows a plan view of a polishing pad according to another preferred embodiment of the present invention.

FIG. 6 is a plan view showing a polishing pad according to another preferred embodiment of the present invention.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the accompanying drawings.

(1) Polishing layer

The polyurethane abrasive layer can be prepared by a known prepolymer method, a one-step method and other methods, and the method selected by the technical personnel of the invention according to the needs does not influence the conception and the protection scope of the invention, so long as the abrasive layer related to the invention can be made.

The grinding layer can be prepared from isocyanate prepolymer and curing agent, and physical parameters such as hardness, density, compressibility and the like are controlled by the content of the curing agent and the content of microspheres in the prepolymer with different components. In the prepolymer of this example, various toluene diisocyanates [ TDI ] or MDI and polytetrahydrofuran [ PTMEG ] or polypropylene glycol [ PPG ] are used to form isocyanate prepolymers (Adiprene LF930A, LF950A, LF600D, LF601D, LF650D, LF700D, LF751D, LF753D, ROYALCAST 2505, etc.), 4' -methylene-bis-o-chloroaniline [ MBCA ] is used as the curing agent, and hollow microspheres with the brand number 551DE20d42 are used as the microspheres. And pouring the mixture into a mold to form a cylinder, slicing the cylinder to obtain a sheet, and finally grooving the sheet to obtain the grinding layer with the groove pattern, wherein the prepared grinding layer is about 2 mm.

(2) Buffer layer

Examples of the cushion layer include fibrous nonwoven fabrics such as polyester nonwoven fabrics, nylon nonwoven fabrics, and acrylic nonwoven fabrics; resin-impregnated nonwoven fabrics such as polyurethane-impregnated polyester nonwoven fabrics; high polymer resin foams such as polyurethane foam and polyethylene foam; rubbery resins such as butadiene rubber and isoprene rubber; photosensitive resins, and the like.

The buffer layer is prepared by using polyester non-woven fabrics, the polyester non-woven fabrics with different densities (the polyester non-woven fabrics are provided by Huafeng spandex company) are soaked in DMF (dimethyl formamide) solution of polyurethane with the viscosity of 6000-15000cP, and the preparation method of the polyurethane solution comprises the following steps: 100 parts by mass of prepolymers with different NCO% contents (the NCO content is 7.74-9.45%), 17 parts by mass of BDO and 45 parts of DMF solution are uniformly mixed and react for 200min at 80 ℃ to obtain the required polyurethane solution, and the polyurethane solution can be diluted by using a diluent to adjust the viscosity as required.

The density, hardness and compressibility of the buffer layer can be adjusted by using different non-woven fabrics and polyurethane DMF solutions with different viscosities. After soaking for a period of time, forming and attaching TPU on the non-woven fabric through solution exchange in a coagulating tank of low-concentration DMF, then putting the non-woven fabric into a rinsing bath of clear water to wash off the solvent, then drying the non-woven fabric in a tunnel furnace at 150 ℃, forming, and then polishing to the required thickness.

(3) Polishing pad

The polishing pad of the present invention includes the polishing layer and the cushion layer, and a method for bonding the polishing layer and the cushion layer is not particularly limited, and for example, a method in which an adhesive layer made of a polyester-based hot-melt adhesive is laminated on the cushion layer, the adhesive layer is heated and melted by a heater, and then the polishing layer is laminated on the melted adhesive layer and pressed can be cited.

It is noted that the polishing layer of the polishing pad of the invention optionally further comprises an endpoint detection window, preferably the detection window is an integrity window incorporated into the polishing layer.

Table 1 shows polishing pads of different properties.

TABLE 1 polishing pad compositions of examples and comparative examples

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Implementation mode one

Fig. 1 is a plan view schematically showing a polishing pad according to a preferred embodiment of the present invention. Referring to FIG. 1, the polishing pad of the present invention is suitable for polishing or planarizing at least one of semiconductor, optical, and magnetic substrates. The polishing pad includes an abrasive layer 100. The polishing layer 100 includes at least two concentric grooves, which are circular grooves having concentric circles but different radii. Defining the innermost concentric circular groove as a first concentric circle 11 and the outermost concentric circular groove as a second concentric circle 12; the first concentric circle 11 and the second concentric circle 12 define a plurality of polishing regions, and the distance between the innermost side of the first concentric circle 11 and the center of the polishing layer in the radial direction is W1, the distance between the outermost side of the second concentric circle 12 and the edge 10 of the polishing layer is W3, and the radius of the polishing layer is R, the three polishing regions are as follows:

a first polishing zone having an inner region of a first concentric circle 11 and a width W1;

a second grinding zone having a region between the first concentric circle 11 and the second concentric circle 12 with a width W2 ═ R-W1-W3;

a third grinding zone; having an area between the second concentric circle 12 and the edge 10 of the polishing layer with a width W3;

the arrangement and the size of the grooves of the grinding layer directly influence the grinding performance of the polishing pad, the invention defines the proportional relation between the widths of the three grinding areas and the radius R of the polishing pad, and the W2/R is defined to be in the range of 0.78-0.94; limiting the W1/R to be in the range of 0.01-0.10; the W3/R is limited to a range of 0.05-0.12, more preferably 0.06-0.10.

Under the above three region limitations, the present invention has studied the groove arrangement of the second polishing region and the third polishing region. The second polishing zone of the first embodiment further comprises a plurality of concentric circular grooves, e.g., 11a, 11b, 11 c; the third polishing zone has a third groove 13 comprising a series of linear grooves, e.g. 13a, 13 b. The outer side end of the third groove is connected with the edge 10 of the grinding layer, the third groove extends along the radial direction, and the inner side end of the third groove is arranged in the second area; and the number of the third grooves is 2 xK, K is more than or equal to 1 and less than or equal to 48, and K is an integer. The trench design has good polishing rate and low defectivity. Preferably, the number of the third trenches is a multiple of 4, and more preferably, the number of the third trenches is a multiple of 8.

As another embodiment of the present invention, the third groove may also form an angle with the radial direction, the angle is in the range of 0 to 90 °, when the angle is 0 °, the third groove extends in the radial direction as shown in fig. 1.

With continued reference to FIG. 2, FIG. 2 is a schematic cross-sectional view of FIG. 1 taken along section line A-A, with polishing pad 1 including an abrasive layer (Top pad)2T and a buffer layer (Sub pad) 3S; the invention carries out a great deal of research aiming at the groove patterns, the grinding layer and the buffer layer of the polishing pad, and finally designs the polishing pad with excellent comprehensive performance.

The width of the concentric grooves defining the second region is Wa, the pitch between two adjacent grooves is P, and the depth Da of the grooves is defined as the distance from the grooves to the polishing surface of the polishing layer in the vertical direction. Similarly, the depth of the third groove is Db; the length of the third trench is defined as Lb, which is the distance between the outer end and the inner end.

In view of the above dimensions, the present invention defines a Wa/P range of 0.05 to 0.35; for example, 0.07, 0.10, 0.12, 0.13, 0.15, 0.17, 0.20, 0.22, 0.25, 0.26 and the like are preferable, and the range of 0.1 to 0.3 is more preferable.

The present invention further defines the ratio of the width W2 of the second polishing region to the pitch P of the concentric grooves disposed therein, and the ratio W2/P is defined as 70-380, more preferably 100-380, which can approximately represent the number of grooves, and the number of concentric grooves of the second polishing region can preferably be a multiple of 8 such as 112, 120, 128, 136, 144, 160, 176, 192, 200, 208, 224, etc.

The physical parameters of the polishing layer and the buffer layer have important influences on the polishing performance, especially the polishing rate, defectivity and polishing nonuniformity. As a preferred embodiment of the present invention, the abrasive layer has a hardness in the range of 50-67D and a density in the range of 0.66-0.87g/cm³The compressibility ranges from 0.001 to 0.06. The buffer layer has a hardness of 59-86A and a density of 0.25-0.4g/cm³The compressibility ranges from 0.02 to 0.12.

More preferably, the difference between the hardness of the polishing layer and that of the buffer layer is in the range of 29-45.5D, and the difference between the density of the polishing layer and that of the buffer layer is in the range of 0.32-0.46g/cm³The range of the absolute value of the compressibility difference is 0.025-0.089.

More preferably, the abrasive layer has a hardness in the range of 54-64D and a density in the range of 0.67-0.73g/cm³The compressibility ranges from 0.001 to 0.025. More preferably, the buffer layer has a hardness in the range of 67-77A and a density in the range of 0.27-0.35g/cm³The compressibility ranges from 0.05 to 0.09. More preferably, the difference between the hardness of the polishing layer and that of the buffer layer is in the range of 35-45D, and the difference between the density of the polishing layer and that of the buffer layer is in the range of 0.35-0.43g/cm³。

The design research is carried out on the concentric circular grooves of the second grinding area, and according to the sequence of the radius from small to large, the concentric circular grooves are counted as the 1 st, the 2 nd, the 3 rd and the m th, so that the 1 st groove is the concentric circular groove 11, and the m th groove is the concentric circular groove 12. Accordingly, the areas are S1, S2, S3, …, Sm.

The calculation can be known that the number of the current,

S1＝π(W1+Wa)²-πW1²＝π(2W1*Wa+Wa²)

S2＝π[2(W1+P)*Wa+Wa²]

S3＝π[2(W1+2P)*Wa+Wa²]

…

Sm＝π[2(W1+(m-1)P)*Wa+Wa²]

total groove area Sa ═ pi { mWa²+2Wa[m*W1+m(m-1)*P/2]}

W2 ═ P + Wa (m-1), then m ═ 1+ (W2-Wa)/P

The total groove area Sa is obtained by converting the number m of grooves by W2, Wa, and P:

sa ═ π Wa (2W1+ W2) (W2/P-Wa/P +1), in the preferred embodiment, the area is limited to the range of 42000 and 300000mm²。

Further preferably, the groove width Wa is 0.1 to 0.6mm, preferably 0.2 to 0.55 mm. The groove pitch P is 1 to 5mm, preferably 1 to 4 mm.

As can be seen from the above equation of the groove area, the area of the groove is related to the width Wa of the groove, the width W1 of the first polishing region, the width W2 of the second polishing region, and the parameters W2/P and Wa/P. The groove area is an important factor affecting the groove polishing rate, and therefore the present invention is defined with respect to the above parameters, for example, Wa/P is in the range of 0.05-0.35, and W2/P is in the range of 70-380.

Definition Sa ═ pi × Wa (2W1+ W2) (W2/P-Wa/P +1), and in the embodiment of the present invention, the range of Sa is preferably 42000-300000mm²。

In the present invention, the parameters of the first, second and third polishing zones are within the ranges defined by W1/R, W2/R, W3/R, Wa/P and W2/P, and it is preferable that the inner ends of the third grooves of the third polishing zone are disposed in the second polishing zone, the third grooves have a length Lb, and preferably Lb and W3 satisfy the relationship: w3. ltoreq. Lb.ltoreq.2.7W 3, more preferably W3. ltoreq. Lb.ltoreq.2.05W 3.

According to the invention, the third groove is preferably connected with the concentric circular grooves of the second area, and the inner side end of the third groove is defined to be connected with the nth concentric circular groove from outside to inside of the second area, so that n is an integer ranging from 1 to 12.

Preferably, the third trench is a straight line, and with continued reference to fig. 2, the length of Lb may be calculated using W3 and P: Lb-W3 + (n-1) × P, n preferably ranges from 3 to 10 integers.

It is preferable in the present invention that the width Wb of the third groove is in the range of 0.5 to 6mm, more preferably 2.5 to 4.5 mm.

Fig. 3 is a partially enlarged view of fig. 2, in a first embodiment, a third trench is connected to a 3 rd concentric circular trench from outside to inside, and grooving is performed after the third trench is positioned in an actual grooving process, but a certain radian exists at a connection position of the third trench and the concentric circular trench inevitably due to a cutting process, as can be seen from fig. 3, in this embodiment, the length of Lb still satisfies Lb ═ W3+ (n-1)' P.

The invention further defines that the total area Sb of the third grooves and the total area Sa of the second region concentric circular grooves satisfy 0.01 < Sb/Sa < 0.4, and can be 0.01, 0.03, 0.04, 0.05, 0.07, 0.1, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40. The area ratio affects the distribution of the polishing liquid and the efficiency of removing the waste residue, and is more preferably 0.01 to 0.20.

In one embodiment, the total area Sb of the third trench is 2 × K × Lb.

The depth Da of the second grinding is defined to be 0.1-0.8 times the thickness of the grinding layer. The third grooves have the depth Db, and experimental researches show that the depth Db of the third grooves has a certain correlation with the depth Da of the concentric-circle grooves, the range of Db/Da is further limited to be 0.5-1.5, the range of Db/Da is further limited to be 0.8-1.2, and the polishing performance is better.

The ratio Vb/Va (Sb × Db)/(Sa × Da) is defined to approximately represent the ratio of the total volume Vb of the third trenches to the total volume Va of the concentric circular trenches of the second region, and is in the range of 0.005 to 0.6, and more preferably in the range of 0.008 to 0.24. For example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24 may be mentioned. The volume ratio is within the range, the whole transport capacity of the polishing solution in the groove and the whole slag discharge capacity of the waste liquid can be reasonably balanced, and the polishing pad has excellent grinding performance.

Second embodiment

As another preferred embodiment of the present invention, similar to the first embodiment, the groove pattern of the present invention is combined, and the buffer layer property is preferably defined for the polishing layer of the polishing pad.

As a preferred embodiment of the present invention, the abrasive layer has a hardness in the range of 50-67D and a density in the range of 0.66-0.87g/cm³The compressibility ranges from 0.001 to 0.06. The buffer layer has a hardness of 59-86A and a density of 0.25-0.4g/cm³The compressibility ranges from 0.02 to 0.12.

More preferably, the abrasive layer has a hardness in the range of 54-64D and a density in the range of 0.67-0.73 g-cm³The compressibility ranges from 0.001 to 0.025. More preferably, the buffer layer has a hardness in the range of 67-77A and a density in the range of 0.27-0.35g/cm³The compressibility ranges from 0.05 to 0.09. More preferably, the difference between the hardness of the polishing layer and that of the buffer layer is in the range of 35-45D, and the difference between the density of the polishing layer and that of the buffer layer is in the range of 0.35-0.43g/cm³。

With further reference to FIG. 4, the polishing pad includes an abrasive layer 200, the abrasive layer 200 being in direct contact with the material being abraded. The dimensions and parameter ranges of the first polishing region and the second polishing region in the second embodiment are similar to those in the first embodiment, and the description thereof is not repeated.

The third grooves of the third polishing zone of the polishing layer 200 also include two types of grooves, a main groove 23 and a secondary groove 24, which are also a series of linear grooves, such as

main grooves

23a, 23 b; the sub-trenches 24a, 24b, etc. The outer side ends of the different types of third grooves are connected with the edge of the grinding layer, the different types of third grooves extend along the radial direction, and the inner side ends of the third grooves are arranged in the second area; the total number of the third grooves is 2 xK, K is more than or equal to 1 and less than or equal to 48, and K is an integer. Preferably, the total number of the different types of the third trenches is a multiple of 4, and more preferably the total number of the third trenches is a multiple of 8.

Defining the length of the third groove as Lb, wherein the lengths of the different types of third grooves can be sequentially marked as Lb1, Lb2 and Lb3 … LbN; one end of the third groove is connected with the edge of the grinding layer, and the other end of the third groove is arranged in the second grinding area. The range of its length LbN is preferably: w3 is not less than LbN not more than 2.7W3, more preferably W3 not more than LbN not more than 2.05W 3. That is, the length ranges of the different types of the third grooves are preferably W3-2.7W3, and more preferably W3-2.05W 3.

According to the invention, the third groove is preferably connected with the concentric circular grooves of the second area, and the inner side end of the third groove is defined to be connected with the nth concentric circular groove from outside to inside of the second area, so that n is an integer ranging from 1 to 12. As shown in fig. 4, the groove 23 is connected to the 5 th groove, and the groove 24 is connected to the 2 nd groove.

Preferably the third trench is a straight line, the length of LbN can be calculated using W3 and P: LbN ═ W3+ (n-1) × P, n preferably ranges from an integer from 1 to 12, preferably from an integer from 2 to 10.

Similarly, the different types of third trench widths may be labeled Wb1, Wb2, Wb3 … WbN, in that order; the width of the different types of third grooves preferably ranges from 0.5 mm to 6 mm; more preferably 2.5-4.5 mm.

The third groove can form a certain included angle with the radial direction, and the angle range is 0-90 degrees.

As described in the first embodiment, the total area of the concentric grooves of the second polishing region is Sa, and the present invention further defines that the total area Sb of the third grooves and the total area Sa of the concentric grooves of the second region satisfy 0.01 ≦ Sb/Sa ≦ 0.4, and may be, for example, 0.01, 0.03, 0.04, 0.05, 0.07, 0.1, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40. The area ratio affects the distribution of the polishing liquid and the efficiency of removing the waste residue, and is more preferably 0.01 to 0.20.

In embodiment two, the total area of the third trenches is the sum of the areas of the different types of third trenches.

The third groove has a depth Db, which is the distance from the groove to the polishing surface of the polishing layer. Experimental research shows that the depth Db of the third grooves has certain correlation with the depth Da of the concentric grooves, and the range of Db/Da is further limited to be 0.5-1.5. The invention further limits the Db/Da range to be 0.8-1.2, and the polishing performance is better.

Third embodiment

The third grooves of the present invention are linear grooves, for example, the third grooves of the first to second embodiments are all linear grooves, and as another preferred embodiment of the present invention, the third grooves of the third polishing region of the polishing pad may also be curved. In combination with the groove pattern of the present invention, the polishing layer and the buffer layer of the polishing pad have more preferable limitations, which are the same as those of the first to second embodiments and will not be described repeatedly.

With further reference to FIG. 5, the polishing pad includes an abrasive layer 300, the abrasive layer 300 being in direct contact with the material being abraded. The polishing layer 300 includes at least two concentric grooves, the first and second concentric circles defining a plurality of polishing regions; the dimensions and parameter ranges of the first polishing region and the second polishing region in the third embodiment are similar to those in the first embodiment, and the description thereof is not repeated.

The third grooves 33 of the third polishing region of the polishing layer 300 are a series of curved linear grooves, such as 33a, 33 b. The outer side end of the third groove is connected with the edge of the grinding layer, the inner side end of the third groove is arranged in the second area, the number of the third grooves is 2X K, K is more than or equal to 1 and less than or equal to 48, and K is an integer.

Preferably, the number of the third trenches is a multiple of 4, and more preferably, the number of the third trenches is a multiple of 8.

The length of the third groove is defined as Lb, the length of the curve groove is defined as the distance between the curve outer side end and the curve inner side end. The range of the length Lb is the same as that of the first embodiment, and preferably Lb and W3 satisfy the relationship: w3. ltoreq. Lb.ltoreq.2.7W 3, more preferably W3. ltoreq. Lb.ltoreq.2.05W 3.

According to the invention, the third groove is preferably connected with the concentric circular grooves of the second area, and the inner side end of the third groove is defined to be connected with the nth concentric circular groove from outside to inside of the second area, so that n is an integer ranging from 1 to 12, and preferably ranges from 3 to 10.

The width of the curve groove is similar to that of a straight line, namely the line width of the curve, and the range of the width Wb is 0.5-6 mm; more preferably 2.5-4.5 mm.

Embodiment IV

As another preferred embodiment of the present invention, the third grooves of the third polishing region of the polishing pad may also be a combination of curves. In combination with the groove pattern of the present invention, the polishing layer and the buffer layer of the polishing pad have more preferable limitations, which are the same as those of the first to third embodiments and will not be described repeatedly.

With further reference to FIG. 6, the polishing pad includes an abrasive layer 400, the abrasive layer 400 being in direct contact with the material being abraded. The polishing layer 400 includes at least two concentric grooves, the first and second concentric circles defining a plurality of polishing regions; the dimensions and parameter ranges of the first polishing region and the second polishing region in the third embodiment are similar to those in the first embodiment, and the description thereof is not repeated.

The third grooves of the third polishing zone of the polishing layer 400 also include two types of grooves, a primary groove 43 and a secondary groove 44, both of which are also a series of curvilinear grooves, such as

primary grooves

43a, 43 b; the sub-trenches 44a, 44b, etc. The outer side ends of the different types of third grooves are connected with the edge of the grinding layer, the different types of third grooves extend along the radial direction, and the inner side ends of the third grooves are arranged in the second area; the total number of the third grooves is 2 xK, K is more than or equal to 1 and less than or equal to 48, and K is an integer. Preferably, the total number of the different types of the third trenches is a multiple of 4, and more preferably the total number of the third trenches is a multiple of 8.

The length of the third groove is defined as Lb, the length of the curve groove is defined as the distance between the curve outer side end and the curve inner side end. The different types of third trench lengths may be labeled in order Lb1, Lb2, Lb3 … LbN; one end of the third groove is connected with the edge of the grinding layer, and the other end of the third groove is arranged in the second grinding area. The range of its length LbN is preferably: w3 is not less than LbN not more than 2.7W3, more preferably W3 not more than LbN not more than 2.05W 3. That is, the length ranges of the different types of the third grooves are preferably W3-2.7W3, and more preferably W3-2.05W 3.

According to the invention, the third groove is preferably connected with the concentric circular grooves of the second area, and the inner side end of the third groove is defined to be connected with the nth concentric circular groove from outside to inside of the second area, so that n is an integer ranging from 1 to 12, preferably an integer ranging from 2 to 10. As shown in fig. 6, the groove 43 is connected to the 5 th groove, and the groove 44 is connected to the 2 nd groove.

Similarly, the different types of third trench widths may be labeled Wb1, Wb2, Wb3 … WbN, in that order; the width of the curved groove is the width of the groove line. The width of the different types of third grooves preferably ranges from 0.5 mm to 6 mm; more preferably 2.5-4.5 mm.

Other variants, such as the third trench also include different types of trenches: such as different types of linear and curved grooves, are also preferred embodiments of the present invention. The length, the width, the Sb/Sa, the Vb/Va and other parameters of the third grooves are within the preferable range, and the comprehensive performance of the polishing pad is better.

As a result of extensive experimental studies, the present inventors have found that the polishing layer has the above-defined groove pattern, and has a hardness in the range of 50 to 67D and a density in the range of 0.66 to 0.87g/cm³Compressibility ranges from 0.001 to 0.06, while the hardness of the buffer layer ranges from 59 to 86A and density ranges from 0.25-0.4g/cm³The compressibility ranges from 0.02 to 0.12. The polishing pad not only has good polishing rate, defectivity and low non-uniformity, but also maintains the loss rate cut at a low level while maintaining good polishing performance. Particularly, the hardness difference between the polishing layer and the buffer layer of the polishing pad is 29-45.5D, and the density difference is 0.32-0.46g/cm³And when the absolute value range of the compression rate difference is 0.025-0.089, the comprehensive performance is optimal.

Examples

Code number explanation:

w1: width of the first polishing zone, unit: mm;

w2: width of the second polishing zone, unit: mm;

w3: width of the third polishing zone, unit: mm;

r: radius of polishing pad, unit: mm;

wa: the width of the concentric groove of the second grinding area is unit mm;

p: the groove pitch of the concentric circular grooves of the second grinding area is unit mm;

n: a third number of trenches;

lb: the length of the third groove is in mm;

wb: the width of the third groove is unit mm;

da: depth of concentric groove in unit mm;

db: the depth of the third groove is in mm;

sa, Sb: the total area of the concentric grooves and the total area of the third grooves are respectively in mm²；

Vb/Va (Sb × Db)/(Sa × Da) is defined to approximately characterize the volume ratio of the third grooves to the concentric grooves.

Polishing pad physical property test method:

compression ratio:

using a cylindrical indenter with a diameter of 5mm at Mac Test materials (samples) were tested on TMA manufactured by Science at 25 ℃ Product size: diameter 7mm) was applied, and T1(μm) was measured)、T2(μm)。

Compression ratio (%) [ (T1-T2)/T1]×100

²Wherein T1 represents the sheet thickness after applying a stress of 30kPa (300g/cm) to the sheet and holding for 60 seconds, and T2 represents The sheet in state T1 was stressed at 180kPa and held for 60 seconds.

Hardness D and A: according to ASTM D2240.

Density: according to ASTM D1622 measurement.

Grinding parameters and evaluation methods:

the polished wafer was TEOS 8K wafer, the slurry was slurry D3000 of silica abrasive, the flow rate was 200ml/min, the dresser was a Saeseol diamond disk of AJ45, the pressure was 7lbf, the pressure of the polishing head was 3.5psi, the platen speed was 110rpm, the carrier speed was 108rpm, and the polishing time was 45 s.

Loss rate (cut rate) measurement method: the polishing pad was dressed using AJ45 from Saeseol diamond disk at 60 minutes pressure of 7lbf with deionized water at 500ml/min platen speed of 93rpm and carrier speed of 87 rpm. The rate of wear is determined by measuring the change in thickness of the pad over time.

For the 10 th and 100 th wafers, the polishing rate, polishing non-uniformity and defectivity were measured.

The lapping rate was calculated by measuring the lapping removal at various locations on the wafer over a polishing time using a Nano SpecII tool.

The polishing rate heterogeneity (Nu) was also calculated from the Nano SpecII.

The defectivity is a count of defects on the wafer measured using a KLA-Tencor SP2 analyzer.

TABLE 2 groove geometry data for polishing pad samples

Note: the third trench of example 8 is curved as shown in fig. 5; the remaining third grooves are all straight lines, as shown in fig. 1.

TABLE 3 polishing pad sample abrasive layer size calculation parameters

Examples of the invention	W1/R	W2/R	W3/R	Wa/P	W2/P	Sa	Lb/W3	Sb/Sa	Vb/Va	Db/Da
											1	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
2	0.04	0.87	0.08	0.33	222.01	132259.9	1.430	0.043	0.043	1
											3	0.04	0.87	0.08	0.10	111.01	39906.0	1.285	0.127	0.127	1
4	0.04	0.87	0.08	0.17	111.01	66426.9	1.285	0.153	0.153	1
											5	0.10	0.85	0.05	0.17	107.50	69992.41	1.290	0.095	0.095	1
6	0.01	0.87	0.12	0.17	111.05	61788.89	1.203	0.216	0.216	1
											7	0.04	0.87	0.08	0.17	166.51	149086.5	1.445	0.057	0.057	1
8	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.093	0.093	1
											9	0.04	0.84	0.12	0.17	106.74	61662.94	1.475	0.389	0.584	1.5
10	0.04	0.87	0.08	0.17	111.01	66426.9	1.095	0.010	0.010	1
											11	0.04	0.87	0.08	0.17	111.01	66426.9	1.000	0.059	0.059	1
12	0.04	0.87	0.08	0.17	111.01	66426.9	2.050	0.122	0.122	1
											13	0.04	0.87	0.08	0.17	111.01	66426.9	1.190	0.071	0.071	1
14	0.04	0.87	0.08	0.17	111.01	66426.9	1.860	0.110	0.110	1
											15	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
16	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
											17	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
18	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
											19	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
20	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
											D1	0.04	0.87	0.08	0.17	111.01	66426.9	0.900	0.053	0.053	1
D2	0.11	0.76	0.14	0.17	96.24	58122.61	1.113	0.125	0.125	1
											D3	0.10	0.79	0.12	0.11	64.07	39415.57	1.422	0.200	0.200	1
D4	0.04	0.87	0.08	0.17	383.03	151470.6	1.248	0.049	0.049	1
											D5	0.04	0.87	0.08	0.04	96.67	17121.79	1.437	0.331	0.331	1
D6	0.04	0.87	0.08	0.40	222.01	158768.2	1.190	0.030	0.030	1
											D7	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
D8	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
											D9	0.04	0.87	0.08	0.17	111.01	66426.9	1.476	0.088	0.088	1
D10	0.02	0.98	0	0.17	124.62	79016.4	0	0	0	0

Note: the third trench area of example 8 can be directly obtained by the mapping software.

TABLE 4 evaluation of polishing Properties

As can be seen from examples 1-20, the polishing layer had a hardness of 50-67D and a density of 0.66-0.87g/cm³Compressibility ranges from 0.001 to 0.06; the buffer layer has a hardness of 59-86A and a density of 0.25-0.4g/cm³The compression ratio is in the range of 0.02-0.12; at W2/PThe range is 70-380, the range of W2/R is 0.78-0.94; the range of Wa/P is 0.05-0.35; the polishing pad is very suitable for planarization of oxide of the material to be polished and has a better polishing rate (greater than that of the third grooves) when the polishing pad has W1/R in the range of 0.01-0.10 and W3/R in the range of 0.05-0.12 and includes the third grooves with the inner ends arranged in the second polishing region

) Defectivity (less than 90), polishing rate non-uniformity (not higher than 6%), and loss rate at a low level of not higher than 43 μm/hr while maintaining excellent overall performance.

The material properties of the polishing pad and the groove pattern all have an important influence on the performance of the polishing pad of the present invention, and as can be seen from examples and comparative examples,

the length of the third trench of comparative example 1 is less than W3, the defectivity increases to more than 110, and the non-uniformity is poor to 6.6%; comparative example 2, in which W1/R, W2/R and W3/R exceeded the respective ranges, showed a significant increase in the defect rates, i.e., 190(10) tablets and 204 (100) tablets, and exhibited a deterioration in the nonuniformity of 8.2%; too few (comparative example 3) or too many (comparative example 4) grooves in concentric circles adversely affect the defect level and non-uniformity, and the defect level rises to 230 or more; comparative example 5 has a Wa/P of 0.04, lower than the appropriate range of 0.05 to 0.35, resulting in a very high defect level, rising to 386(10 chips) and 411(100 chips); comparative example 6 has a Wa/P of 0.40, higher than the appropriate range of 0.05 to 0.35, higher defectivity of 405(10 sheets) and 388(100 sheets), and also higher depletion rate cut of 47.5 μm/hr; the buffer layer of comparative example 7 was too soft, had a hardness of 50A and a density of 0.22g/cm³The compressibility of 0.15 is out of the proper range, and other groove geometric parameters are in the preferable range, but the polishing pad has a very low polishing rate, and the defectivity and the non-uniformity of the wafer are poor; the buffer layer of comparative example 8 was too hard, had a hardness of 90A and a density of 0.43g/cm³All out of the appropriate range, other groove geometry parameters are preferred, but defectivity increases significantly, up to 388(10 pieces) and 414(100 pieces), and pad wear is most severe, with wear rates up to 55.2 μm/hr; the parameters of the polishing layer and the buffer layer of the comparative example 9 are out of the proper ranges, and the defect degree is highest. Comparative example 10 isIn comparison with conventional concentric grooves, the defectivity and polishing non-uniformity of the present invention are significantly lower, and the loss rate (cut rate) is lower.

In summary, the polishing layer has a hardness of 50-67D and a density of 0.66-0.87g/cm³Compressibility ranges from 0.001 to 0.06; the buffer layer has a hardness of 59-86A and a density of 0.25-0.4g/cm³The compression ratio is in the range of 0.02-0.12; in combination with the preferred ranges of the geometric parameters, the resulting polishing pad has superior performance.

Through a plurality of experimental researches and creative labor, various factors are comprehensively considered, and the obtained polishing pad which meets the parameter range has the optimal polishing performance.

Claims

1. A polishing pad comprising an abrasive layer having a hardness in the range of 50-64D and a density in the range of 0.66-0.87g/cm³Compressibility ranges from 0.001 to 0.06; the grinding layer is in direct contact with a ground material and comprises at least two concentric circular grooves, the innermost concentric circular groove is defined as a first concentric circle, and the outermost concentric circular groove is defined as a second concentric circle; the first concentric circle and the second concentric circle define a plurality of polishing regions, and are defined in a radial direction, wherein a distance from an innermost side of the first concentric circle to a center of the polishing layer is W1, a distance from an outermost side of the second concentric circle to an edge of the polishing layer is W3, and a radius of the polishing layer is R, wherein:

a second grinding zone having a region between the first concentric circle and the second concentric circle with a width W2= R-W1-W3;

the range of W2/P is 70-380, and the range of W2/R is 0.78-0.94;

the width of the concentric circular grooves of the second grinding area is Wa, the distance between the grooves is P, and the range of Wa/P is 0.05-0.35;

the range of W1/R is 0.01-0.10, and the range of W3/R is 0.05-0.12;

the third grinding area further comprises third grooves, the outer side ends of the third grooves are connected with the edge of the grinding layer, the inner side ends of the third grooves are arranged in the second grinding area, the number of the third grooves is 2 x K, K is more than or equal to 1 and less than or equal to 48, and K is an integer; the length of the third groove is Lb, and Lb is more than or equal to W3 and less than or equal to 2.7W 3;

2. The polishing pad of claim 1, wherein the difference in hardness between the abrasive layer and the buffer layer is in the range of 29-45.5D and the difference in density is in the range of 0.32-0.46g/cm³The absolute value of the difference in compressibility ranges from 0.025 to 0.089.

3. The polishing pad of claim 1 or 2, wherein the inner ends of the third grooves are connected to the nth concentric circular grooves from outside to inside of the second polishing region, and n is an integer of 1 to 12.

4. The polishing pad according to claim 1 or 2, wherein a total area Sb of the third grooves and a total area Sa of the second polishing zone concentric circular grooves satisfy: Sb/Sa is more than or equal to 0.01 and less than or equal to 0.4.

5. The polishing pad according to claim 1 or 2, wherein the third grooves have a width Wb in the range of 0.5 to 6 mm.

6. The polishing pad of claim 1, wherein W3/R is in the range of 0.06-0.10.

7. The polishing pad of claim 1, wherein the abrasive layer has a hardness ranging from 54-64D and a density ranging from 0.67-0.73g/cm³The compressibility ranges from 0.001 to 0.025.

8. The polishing pad of claim 1, wherein the buffer layer has a hardness ranging from 67 to 77A and a density ranging from 0.27 to 0.35g/cm³The compressibility ranges from 0.05 to 0.09.

9. The polishing pad of claim 2, wherein the difference in hardness between the abrasive layer and the buffer layer is in the range of 35-45D and the difference in density is in the range of 0.35-0.43g/cm³。

10. The polishing pad according to claim 4, wherein a total area Sb of the third grooves and a total area Sa of the second polishing zone concentric circle grooves satisfy: Sb/Sa is more than or equal to 0.01 and less than or equal to 0.2.

11. The polishing pad of claim 3, wherein the third grooves are straight lines, the third grooves have a length Lb, Lb = W3+ (n-1) × P, n is an integer of 3-10; the width of the third groove is Wb, and the range of Wb is 2.5-4.5 mm.

12. The polishing pad of claim 3, wherein the third grooves have a depth Db, and the concentric circular grooves have a depth Da, defining Vb/Va = (Sb x Db)/(Sa x Da), wherein Vb/Va is in the range of 0.005-0.6.