CN112757154B

CN112757154B - Polishing pad

Info

Publication number: CN112757154B
Application number: CN202110087557.3A
Authority: CN
Inventors: 黄学良; 蔡长益; 刘敏; 桂辉辉; 罗乙杰; 杨佳佳; 邱瑞英; 张季平
Original assignee: Hubei Dinglong Co ltd; Hubei Dinghui Microelectronics Materials Co ltd; Changxin Memory Technologies Inc
Current assignee: Hubei Dinghui Microelectronics Materials Co ltd; Hubei Dinglong Co ltd; Changxin Memory Technologies Inc
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2024-05-10
Anticipated expiration: 2041-01-22
Also published as: CN112757154A

Abstract

The invention discloses a polishing pad, which comprises a polishing layer, wherein the polishing layer comprises a polishing surface and at least one polishing unit positioned on the polishing surface, the polishing units form a polishing unit group, one end of the polishing unit group forms a contact surface, the contact surface is in direct contact with a material to be ground, and each polishing unit is projected into a parallelogram on the contact surface; the plurality of polishing units respectively form a first part and a second part, wherein the first part extends along a first direction and is uniformly spaced, and the second part extends along a direction parallel to the first direction and is uniformly spaced; and, the polishing unit has a passage on a face of the contact surface and includes a first passage and a second passage; the polishing pad of the invention has excellent comprehensive performance when the structure is combined with the defined polishing unit area ratio, the effective channel volume ratio, the effective channel width ratio and other parameters.

Description

Polishing pad

Technical Field

The present invention relates to polishing pads having a well-designed surface trench structure for chemical mechanical polishing of materials to be abraded, such as thin films and devices on semiconductor wafers.

Background

In the fabrication of integrated circuits, other electronic devices, and optical materials, polishing, thinning, or planarizing processes are involved in many materials, the most commonly used of which is chemical mechanical polishing. The chemical mechanical polishing is based on the principle that the polishing liquid acts on a polishing pad on a fixed polishing machine table, the polishing pad contacts with the surface of a material to be polished to generate chemical reaction, and meanwhile, the polishing pad and the material to be polished do rotary motion on the polishing machine table to generate shearing mechanical action, and the polishing treatment is carried out on the material to be polished by the chemical action and the mechanical action together so as to form a desired pattern structure.

Therefore, the flow and distribution of the polishing liquid, 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 the effect on these factors will be different for different patterns and materials, and many attempts have been made on the groove structure of the polishing pad.

EP0829328A2 of h.f.leinhat et al discloses a surface structure of a polishing pad of concentric circles, grooves, spirals, rays, lattices to promote the flow of a polishing liquid, but does not disclose a relation between specific parameters of a surface groove structure of the polishing pad and polishing performance, or how to obtain a polishing effect excellent in comprehensive performance.

US20060014477A1 of r·v·lapachox discloses a design with oscillating structure in the radial direction, which varies the residence time of the polishing liquid in different areas, but also does not disclose specific design parameters as a function of polishing performance.

JP2006167907A, which is published by G.P. Ma Erdao, discloses a polishing slurry having a special groove structure spaced apart from each other in order to improve the flow rate of the polishing slurry, thereby reducing the waste of the slurry.

TW201904719A of J.V.Raney et al discloses grooves of non-isosceles trapezoid structure and illustrates that concentric groove structures are the most popular groove pattern and it is believed that polishing pads of non-isosceles trapezoid structure have better polishing effect.

The prior art discloses various groove structures, but there is no intensive study on the relation between a specific groove structure and polishing performance and how to optimize the groove structure, but the study on polishing performance is taken as an experimental science, has an influence relation among complex factors, is not quite sufficient in theory, so that the relation between the groove structure and polishing performance of a polishing pad is highly desired at present, and a polishing pad with excellent comprehensive polishing performance is designed.

According to the invention, the polishing units are arranged on the polishing pad, and the small channels are designed on the polishing units, so that the polishing pad with excellent comprehensive polishing performance is optimized through a great amount of experimental researches.

Disclosure of Invention

The invention provides a polishing pad, which comprises a polishing layer, wherein the polishing layer comprises a polishing surface and at least one polishing unit positioned on the polishing surface, the polishing unit has an average height D1, the polishing units form a polishing unit group, one end of the polishing unit group forms a contact surface, the contact surface is in direct contact with a material to be ground, and the projection of each polishing unit on the contact surface is in a parallelogram;

The polishing units of the first part extend in a first direction and are uniformly spaced, the polishing units of the second part extend in a direction parallel to the first direction and are uniformly spaced, the spacing of the polishing units of the first part is equal to the spacing of the polishing units of the second part, and the spacing distance in the first direction is W1;

The polishing unit consists of a plurality of first parts and second parts, wherein the first parts and the second parts are equally spaced with each other, and the spacing distance in the second direction is W2; the surface of the contact surface of the polishing unit is provided with channels, the channels are straight, and comprise a plurality of first channels and a plurality of second channels, the first channels are parallel to the first direction, and/or the second channels are parallel to the second direction;

the contact surface of the polishing unit has an area S1, the side lengths of the parallelogram projected on the contact surface by the polishing unit in the first direction and the second direction are L1 and L2 respectively, and the included angle between the first direction and the second direction is theta, and the method comprises the following steps:

S1＝L1*L2*sinθ

the projection of the channels on the contact surface of the polishing units has an area Sa, and on each polishing unit, the first channels have the number n, the average width Waa and the length L1; the number of the second channels is m, the average width is Wab, the length is L2, the average depth of the channels is Da, wherein n, m is an integer, m+n is more than or equal to 1, the number of intersection points Nb=m×n, and the method comprises the following steps:

Sa＝n*Waa*L1*sinθ+m*Wab*L2*sinθ-Nb*Waa*Wab*sinθ

The effective contact area Ss of the polishing unit is as follows:

Ss＝S1-Sa＝sinθ*(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)

the polishing layer effective contact area ratio RS3 is defined as follows:

RS3＝Ss/((L1+W1)*(L2+W2)*sinθ)

= ((l1+w1) (l2+w2)) RS3 ranges from 50 to 85%;

the polishing surface and the ratio r1=l1×l2/((l1+w1) ×l2+w2), the range of RS1 being 0.60 to 0.92;

the effective contact area ratio of the polishing units, RS 2=ss/S1, RS2 ranges from 0.5 to 0.97;

Effective channel width ratio rw4= (n waa+m Wab)/(w1+w2), RW4 ranges from 0.1 to 3.75;

effective channel volume ratio rv5= (sa×da)/(sin θ ((l1+w1) ×l2+w2) -l1×l2) ×d1); RV5 is in the range of 0.03-3.4.

In one embodiment of the present disclosure, the polishing units L1 and L2 range from 10 to 20mm.

In one embodiment of the present disclosure, the effective contact area ratio RS3 is in the range of 60-70%.

In one embodiment of the disclosure, the first channels are uniformly spaced apart and/or the second channels are uniformly spaced apart.

In one embodiment of the present disclosure, the polishing elements have the same or about the same height.

In one embodiment of the present disclosure, the channels have the same or substantially the same depth.

In one embodiment of the present disclosure, the average height D1 is 0.2 to 0.8 times the thickness of the polishing layer.

In one embodiment of the present disclosure, the average depth Da of the channels is 0.4-1 times the height D1 of the polishing elements.

In one embodiment of the present disclosure, the Waa and Wab range from 0.15 mm to 0.6mm.

In one embodiment of the present disclosure, the Waa and Wab range from 0.15 mm to 0.4mm.

In one embodiment of the present disclosure, the polishing units have W1 and W2 in the range of 0.5-5mm.

In one embodiment of the present disclosure, the polishing units W1 and W2 range from 0.8 to 3mm.

In one embodiment of the disclosure, the number of the first channels is any one of 2-5, and/or the number of the second channels is any one of 2-5.

In one embodiment of the disclosure, the number of the first channels is any one of 3-5, and/or the number of the second channels is any one of 3-5.

An embodiment of the present disclosure, wherein the projection of the polishing element on the contact surface is rectangular.

An embodiment of the present disclosure, wherein the projection of the polishing element on the contact surface is square.

An embodiment of the present disclosure, wherein W1 is the same or substantially the same as W2.

An embodiment of the present disclosure, wherein L1 is the same or substantially the same as L2.

An embodiment of the present disclosure, wherein the polishing elements have a diamond shape projected on the contact surface.

In one embodiment of the present disclosure, the polishing elements are arranged in a square matrix on the polishing layer, and the center-to-center distances of adjacent polishing elements are equal.

In one embodiment of the present disclosure, the RS2 range is 0.72-0.93.

In one embodiment of the present disclosure, RW4 ranges from 0.15 to 2.

In one embodiment of the present disclosure, RV5 is in the range of 0.05-0.71.

In one embodiment of the present disclosure, the average depth Da of the channels is 0.4 to 0.8 times the height D1 of the polishing elements.

In one disclosed embodiment of the invention, the polishing layer of the polishing pad of the invention optionally further comprises an endpoint detection window, preferably the detection window is an integral window incorporated into the polishing layer.

The above-mentioned embodiments are only some of the specific descriptions made in the technical idea of the present invention, and the present invention should not be construed as being limited to these embodiments.

The invention has the beneficial effects that:

by means of the special groove design structure, the polishing pad with excellent comprehensive polishing performance is obtained.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention, which is to be read in connection with the accompanying drawings, but is not intended to be limited to the schematic drawings representing the proportions and dimensions of the present invention.

Fig. 1 schematically illustrates a perspective view of a polishing pad according to a preferred embodiment of the present invention.

Fig. 2 is a partial enlarged view of a polishing cell group of the polishing pad shown in fig. 1.

Fig. 3 is a partial enlarged view of a polishing unit of the polishing pad shown in fig. 2.

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

Fig. 5 schematically illustrates a plan view of a polishing pad according to another preferred embodiment of the present invention.

Fig. 6 schematically illustrates a plan view of a polishing pad according to another preferred embodiment of the present invention.

Fig. 7 schematically illustrates a plan view of a polishing pad according to another preferred embodiment of the present invention.

Detailed Description

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

As used herein, the term "substantially" is used to describe and illustrate minor variations. For example, two values may be considered "substantially" the same or equal if the difference between the values is less than or equal to ±5% (such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%) of the average value of the values.

Embodiment one

Fig. 1 is a perspective view exemplarily showing a polishing pad according to a preferred embodiment of the present invention, and for convenience of explanation, one direction in fig. 1 is referred to as an a-direction, the other direction is referred to as a B-direction, and a thickness direction of the polishing pad, i.e., a direction perpendicular to a surface of the polishing pad is referred to as a Z-direction.

In the first embodiment, the a direction and the B direction are 90 degrees, that is, sin θ is 1. 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 layer 110 has a polishing surface 10 and polishing cell groups 20, the polishing cell groups 20 are distributed on the polishing surface 10, and the surfaces of the polishing cell groups 20 form a contact surface that directly contacts the material to be polished. The projection of each polishing unit on the contact surface is quadrilateral, preferably parallelogram such as rectangle, diamond and the like; specifically, the polishing cell group 20 includes a first portion 21 and a second portion 22, wherein each of the first portion 21 and the second portion 22 includes at least one polishing cell 23, and the arrangement of the polishing cell group 20 and the size of the polishing cell directly affect the polishing performance of the polishing pad.

With reference to fig. 2, the polishing elements 23 of the first portion 21 are uniformly distributed along a direction parallel to the a direction, defining a length L1 of the polishing elements 23 in the a direction, and a length L2 of the polishing elements 23 in the B direction. Defining the interval between adjacent polishing units 23 in the a direction as W1; the polishing elements 23 of the second portion 22 are also uniformly distributed in parallel to the a direction, and the adjacent polishing elements 23 are also spaced apart by W1 in the a direction. As shown in FIG. 2, the spacing referred to herein refers to the spacing between adjacent faces of adjacent polishing elements, rather than the spacing between the centers of adjacent polishing elements. The first portion 21 and the second portion 22 extend along a direction parallel to the a direction and are uniformly distributed, the interval between the second portion 22 and the first portion 21 in the B direction is defined as W2, and the interval between the first portion and the second portion refers to the interval between two adjacent surfaces in the B direction.

For the above dimensions, the invention preferably L1 is in the range of 10-20 mm; for example, 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be used. Preferably L2 is in the range of 10-20mm, for example 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be taken. Preferably, W1 is in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm may be used. Preferably, W2 is in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm may be used.

With further reference to fig. 3, the polishing elements 23 further comprise channels 23a,23B, and the single polishing element 23 has n channels 23a parallel to the a direction, m channels 23B parallel to the B direction, m and n being integers such that m+n is equal to or greater than 1, and the number of intersections of the channels 23a and 23B is defined as Nb, where nb=m×n. The width of the channels 23a and 23b may be equal or unequal, defining the average width of the channels 23a as Waa, defining the average width of the channels 23b as Wab, and the average width of the channels means the average of the widths of all the channels. Preferably Waa is in the range of 0.15 to 0.6mm, more preferably 0.15 to 0.4mm. Preferably, the Wab range is from 0.15 to 0.6mm, more preferably from 0.15 to 0.4mm.

In the case where the size of the polishing unit 23 is defined as L1, L2 and the interval between adjacent polishing units is defined as W1, W2, the grinding area ratio RS1 = (l1×l2)/((l1+w1) × (l2+w2)) is set, which can approximately characterize the ratio of the total area of the polishing unit 23 to the polishing layer area. The above dimensions satisfy the relationship: (L1+L2)/((L1+W1) (L2+W2)) is less than or equal to 0.6 and less than or equal to 0.92.

As shown in fig. 3, the effective contact area of the polishing element is lower than the area of the polishing element due to the presence of the channels, in the polishing element 23, the length of the channel 23a is equal to the length of the polishing element in the a direction and is L1, the length of the channel 23B is equal to the length of the polishing element in the B direction and is L2, and the channel area of the polishing element is calculated as follows, as defined by Waa, wab, nb: sa=n×waa×l1+m×wab×l2—nb×waa×wab. The invention thus further defines the effective contact area ss=l1×l2- (n×waa×l1+m×wab×l2—nb×wab) of the polishing element.

The effective contact area ratio of the polishing unit 23, RS2 = Ss/S1, is defined by the present invention to be in the range of 0.5 to 0.97, preferably in the range of 0.72 to 0.93.

The ratio of the total effective contact area of the polishing layer to the polishing layer area was characterized using the effective contact area ratio Ss/((l1+w1) (l2+w2) sin θ). The effective contact area ratio of the polishing layer affects the cooperation of mechanical polishing and chemical polishing, and is critical to the grinding performance of the polishing pad. The present invention defines that the effective contact area ratio RS3 satisfies the relationship: and 50% less than or equal to (l1×l2- (n×waa×l1+m×wab×l2—nb×waa)/((l1+w1) (l2+w2)) +.. Further, the ratio ranges more preferably from 60% to 70%, for example, alternatively 62%,63%,64%,65%,66%,67%,68%,69%, etc. ratios.

Referring to fig. 3, an average height D1 of the polishing unit 23 is defined as an average value of distances of the contact surface of the polishing unit 23 from the polishing surface 10 in the Z direction, a depth of the channel is defined as a distance of the channel from the contact surface of the polishing unit in the Z direction, and the average depth Da refers to an average depth of the channels 23a and 23 b.

The width ratio of the channels formed between the channels of the polishing layer and the polishing units is an important parameter affecting the polishing performance of the polishing pad as well as the volume ratio, and the effective channel width ratio is defined as rw4= (n×waa+m×wab)/(w1+w2), and the present invention limits the width ratio to a range of 0.1 to 3.75, more preferably 0.15 to 2. In the present invention, D1 is preferably in the range of 0.2 to 0.8 times the thickness of the polishing layer, da is preferably in the range of 0.4D1 to D1, and Da is more preferably in the range of 0.4D1 to 0.8D1. The effective channel volume ratio is defined as RV5 = (Sa × Da)/(((l1+w1) ((l2+w2) -l1 × l2) × D1 × sin θ), and the present invention limits the volume ratio to a range of 0.03-3.4, more preferably a range of 0.05-0.71.

The number of channels n and m of the present invention is preferably less than 6, for example n, m may each independently be any one of 1,2,3,4, 5; more preferably, any of 2,3,4,5 is taken independently of each other, and most preferably any of 3,4,5 is taken independently of each other.

On the premise that the parameters, such as the RS1, the RS2, the RS3, the RW4, the RV5 and the like, and the preferred sizes accord with the scope of the invention, the first channels and the second channels can be uniformly distributed at intervals or unevenly distributed.

In a preferred embodiment of the present invention, the first channels and the second channels are uniformly spaced apart. Referring to fig. 3, the channels 23a and 23b, which are uniformly spaced apart, may divide the polishing unit 23 into a plurality of sub-units having the same size. The length of the subunit in the B-axis direction is defined as La, and similarly, the length of the subunit in the a-axis direction is Lb, preferably La is in the range of 2mm or more, and preferably Lb is in the range of 2mm or more.

Fig. 4 shows a polishing layer having first channels and second channels unevenly spaced. Specifically, the first and second channels divide the polishing unit 23 into a plurality of sub-units of different sizes, and under the condition that parameters such as the sizes L1, L2, the intervals W1, W2, and the widths and the numbers Waa, wab, n, m, and Da, D1 of the polishing units are the same as those of the example of fig. 3, parameters such as RS1, RS2, RS3, RW4, RV5 are the same, and it is defined that the above parameters are also in the preferred range of the present invention, and the polishing pad has good polishing performance.

In a preferred embodiment of the present invention, the polishing unit is a rectangular parallelepiped or a cube.

In a preferred embodiment of the present invention, the polishing unit is a cube.

In a preferred embodiment of the present invention, the intervals W1 and W2 between the polishing units are equal.

As a preferred embodiment of the present invention, the polishing elements are arranged in a square matrix on the polishing layer, and the center-to-center spacing of each polishing element is equal, i.e., L1 is equal to L2, and W1 is equal to W2.

Second embodiment

Similar to the first embodiment, the direction a and the direction B in the second embodiment are 90 degrees, that is, sin θ is 1. Also, referring to fig. 1, a three-dimensional structure of individual polishing elements may be provided, the polishing layer having a polishing surface and polishing element groups distributed on the polishing surface, the surfaces of the polishing element groups being in direct contact with the semiconductor.

Arrangement pattern of polishing units of polishing layer referring to fig. 5, polishing units 43 of first portion 41 and second portion 42 in the second embodiment are staggered. Preferably, the offset distance is half the side length of the grinding unit in the a direction.

This embodiment is one of the preferred embodiments of the present invention, and as such, the polishing elements 43 include channels, the dimensions of the polishing elements, the dimensions of the channels, and the number of channels in different directions are as defined in embodiment one.

Specifically, the polishing elements 43 of the first portion 41 are uniformly distributed along a direction parallel to the a direction, defining a length L1 of the polishing elements 43 in the a direction, a length L2 of the polishing elements 43 in the B direction, preferably L1 in the range of 10-20 mm; for example, 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be used. Preferably L2 is in the range of 10-20mm, for example 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be taken. The interval between adjacent polishing elements 43 in the A direction is defined as W1, preferably W1 is in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example, 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm can be taken. Although the polishing elements 43 are staggered, the second portions 42 are also parallel to the a direction, and the polishing elements are uniformly spaced along the a direction, i.e., the first portions 41 and the second portions 42 are parallel to each other, so that the spacing between the second portions 42 and the first portions 41 in the B direction is defined as W2, preferably W2 is in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example, 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm.

Similarly, the polishing unit includes a first channel and a second channel, and the number m, n of channels and the definition of the dimensions Waa, wab, and the range of the relevant parameters are as follows:

Defining the polishing area ratio RS1 = (l1×l2)/((l1+w1) × (l2+w2)), the ratio of the total area of the polishing unit 23 to the polishing layer area can be approximated. The above dimensions satisfy the relationship: (L1+L2)/((L1+W1) (L2+W2)) is less than or equal to 0.6 and less than or equal to 0.92.

The effective contact area ratio of the polishing units, r2=ss/S1, is defined to be in the range of 0.5 to 0.97, more preferably 0.72 to 0.93.

Effective contact area ratio RS3 of polishing layer=ss/((l1+w1) (l2+w2) ×sin θ), the effective contact area ratio RS3 satisfies the relationship: and 50% less than or equal to (l1×l2- (n×waa×l1+m×wab×l2—nb×waa)/((l1+w1) (l2+w2)) +.. Further, the ratio ranges more preferably from 60% to 70%, for example, alternatively 62%,63%,64%,65%,66%,67%,68%,69%, etc. ratios.

The width ratio of the effective channels is rw4= (n×waa+m×wab)/(w1+w2), which is limited to a range of 0.1 to 3.75, more preferably 0.15 to 2.

The effective channel volume ratio is RV5 = (Sa × Da)/(((l1+w1) ((l2+w2) -l1+l2) ×d1×sinθ), and the present invention limits the volume ratio to a range of 0.03-3.4, more preferably 0.05-0.71.

Other parameters, such as the number of channels: preferably lower than 6, for example n, m may each independently be any one of 1,2,3,4, 5; more preferably, each of 2,3,4,5 is taken independently; most preferably, each is independently any one of 3,4, 5; the height of the polishing unit; the limitation range of parameters such as the depth of the channel is the same as that of the first embodiment, and the polishing pad shown in fig. 5 has excellent polishing performance and service life within the limitation range.

In a preferred embodiment of the present invention, L1 and L2 of the polishing unit are equal, and W1 and W2 are equal.

Embodiment III

The direction a and the direction B may be right angles or may be other angles, and in the third embodiment, the direction a and the direction B are θ angles. In the first to second embodiments, the θ angle is 90 degrees; in embodiment three, the angle θ may be any angle other than 90 degrees, for example, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 135 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees, and the like.

Also, referring to fig. 1 for a perspective view thereof, the polishing layer has a polishing surface and polishing clusters distributed on the polishing surface, the surfaces of the polishing clusters being in direct contact with the semiconductor.

Referring to fig. 6, the polishing unit group includes a first portion 51 and a second portion 52, wherein each of the first portion 51 and the second portion 52 includes at least one polishing unit 53. Fig. 6 shows an arrangement of the polishing units 53 of the polishing layer.

The polishing unit includes a channel, and the dimensions of the polishing unit and the channel are defined in the first embodiment. Since the polishing elements are parallelograms, their areas correspond to the following:

With continued reference to FIG. 6, the polishing elements 53 are uniformly distributed along a direction parallel to A, with a length L1 in the A direction, preferably L1 in the range of 10-20 mm; for example, 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be used. The length of the polishing unit 53 in the B direction is L2, and preferably L2 is in the range of 10-20mm, for example, 10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm may be used. The spacing between adjacent polishing elements 23 of the first portion 51 and the second portion 52 in the A direction is W1, preferably W1 is in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm may be taken. The second portion 52 is spaced from the first portion 51 in the B direction by W2, W2 being in the range of 0.5-5mm, more preferably in the range of 0.8-3 mm, for example 0.8mm,1mm,1.5mm,1.6mm,2mm,2.5mm,3mm may be taken.

Since the polishing unit 53 is parallelogram, the polishing area s1=l1×l2×sinθ of the polishing unit; polishing area ratio RS 1= (l1×l2×sinθ)/((l1+w1) × (l2+w2) ×sinθ) = (l1×l2)/((l1+w1) ×l2+w2)). The above dimensions satisfy the relationship: (L1+L2)/((L1+W1) (L2+W2)) is less than or equal to 0.6 and less than or equal to 0.92.

The number and size of the channels are the same as those defined in the first embodiment, and since the angle between the a direction and the B direction is θ, the channels are also parallelograms. On each polishing unit, the first channels have a number n, a width Waa being a width of the first channels in the B direction, and a length L1; the second channels have a number of m, a width Wab is a width of the second channels in the a direction, a length is L2, and an average depth Da, where n, m is an integer, m+n is greater than or equal to 1, the number of intersections nb=m×n, as described above, the angle between the a direction and the B direction is θ, the channels are also parallelograms, and the area of a single channel is waa×l1×sinθ or wab×l2×sinθ; the intersection point of the channels is also a parallelogram, and the area of the intersection point is Waa. Thus, the total area of the channel sa=n×waa×l1×sinθ+m×wab×l2×sinθ—nb×waa×wanb×sinθ.

The effective contact area Ss of the polishing unit is as follows:

Ss＝S1-Sa＝sinθ*(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)

The effective contact area ratio RS2 = Ss/(L1L 2) sin θ= (L1L 2-n Waa L1-m Wab l2+nb Wab)/(L1L 2) of the polishing element 53, the present invention defines the ratio in the range of 0.5 to 0.97, more preferably 0.72 to 0.93.

The effective contact area ratio is defined as follows:

RS3＝Ss/((L1+W1)*(L2+W2)*sinθ)

＝sinθ*((L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab))/((L1+W1)*(L2+W2)*sinθ)

= (L1L 2-n Waa L1-m Wab l2+nb Waa Wab)/((l1+w1) (l2+w2)). The present invention defines that the effective contact area ratio RS3 satisfies the relationship: and 50% less than or equal to (l1×l2- (n×waa×l1+m×wab×l2—nb×waa)/((l1+w1) (l2+w2)) +.. Further, the ratio ranges more preferably from 60% to 70%, for example, alternatively 62%,63%,64%,65%,66%,67%,68%,69%, etc. ratios.

Effective channel volume ratio RV5＝(Sa*Da)/(((L1+W1)*(L2+W2)-L1*L2)*D1*sinθ)＝((n*Waa*L1*sinθ+m*Wab*L2*sinθ-Nb*Waa*Wab*sinθ)*Da)/(D1*sinθ*((L1+W1)*(L2+W2)-L1*L2))＝(n*Waa*L1+m*Wab*L2-Nb*Waa*Wab)*Da)/(D1*((L1+W1)*(L2+W2)-L1*L2)), the present invention limits this volume ratio to a range of 0.03-3.4, more preferably 0.05-0.71.

Other parameters, such as the number of channels: preferably lower than 6, for example n, m may each independently be any one of 1,2,3,4, 5; more preferably, each of 2,3,4,5 is taken independently; most preferably, each is independently any one of 3,4, 5; the height of the polishing unit; the limitation range of parameters such as the depth of the channel is the same as that of the first embodiment, and the polishing pad shown in fig. 6 has excellent polishing performance and service life within the limitation range.

In a preferred embodiment of the invention, the projection of the polishing elements on the contact surface is diamond-shaped.

In a preferred embodiment of the invention, the a direction is 45 degrees to the B direction.

Fourth embodiment

Similar to the third embodiment, the a direction and the B direction in the fourth embodiment are at θ degrees. The angle θ may be any angle other than 90 degrees, such as 10 degrees, 20 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 135 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees, etc. Also, referring to fig. 1 for a perspective view thereof, the polishing layer has a polishing surface and polishing clusters distributed on the polishing surface, the surfaces of the polishing clusters being in direct contact with the semiconductor.

Referring to fig. 7, the polishing unit group includes a first portion 61 and a second portion 62, wherein each of the first portion 61 and the second portion 62 includes at least one polishing unit 63. Fig. 7 shows an arrangement of the polishing units 63 of the polishing layer. The polishing elements of the first and second sections of the invention can be distributed in parallel or alternatively in staggered fashion. As shown in fig. 7, the polishing units 63 of the first portion 61 and the second portion 62 in the fourth embodiment are staggered. Preferably, the offset distance is half the side length of the diamond. This embodiment is one of the preferred embodiments of the present invention, and as such, the polishing elements 43 include channels, the dimensions of the polishing elements, the dimensions of the channels, and the number of channels in different directions are as defined in embodiment one.

Specifically, the polishing units 63 of the first portion 61 are uniformly distributed in parallel to the a direction, defining a length L1 of the polishing units 63 in the a direction; the length of the polishing unit 63 in the B direction is L2. Defining the interval between adjacent polishing units 63 in the a direction as W1; although the polishing units 63 are staggered, the second portions 62 are also parallel to the a direction, and the polishing units are also uniformly spaced along the a direction, i.e., the first portions 61 and the second portions 62 are parallel to each other, so that the spacing between the second portions 62 and the first portions 61 in the B direction is defined as W2. Preferred ranges of L1, L2, W1, W2 are the same as in embodiment three.

The parameters of the polishing unit such as size, interval, size, number, area of the channels are the same as those of the third embodiment. Thus, the polishing area s1=l1×l2×sinθ of the polishing unit, and the polishing area ratio RS 1= (l1×l2×sinθ)/((l1+w1) ×l2+w2) ×sinθ) = (l1×l2)/((l1+w1) ×l2+w2). The above dimensions satisfy the relationship: (L1+L2)/((L1+W1) (L2+W2)) is less than or equal to 0.6 and less than or equal to 0.92.

The effective contact area ratio of the polishing elements 63, RS2 = Ss/(L1L 2)/(sin θ= (L1L 2-n Waa L1-m Wab l2+nb Wab)/(L1L 2), is defined by the present invention to be in the range of 0.5 to 0.97, more preferably in the range of 0.72 to 0.93.

Effective contact area ratio Ss/((l1+w1) × (l2+w2) × sin θ)

＝sinθ*((L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab))/((L1+W1)*(L2+W2)*sinθ)

＝(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)/((L1+W1)*(L2+W2))。

The present invention defines that the effective contact area ratio RS3 satisfies the relationship:

And 50% less than or equal to (l1×l2- (n×waa×l1+m×wab×l2—nb×waa)/((l1+w1) (l2+w2)) +.. Further, the ratio ranges more preferably from 60% to 70%, for example, alternatively 62%,63%,64%,65%,66%,67%,68%,69%, etc. ratios.

The width ratio of the effective channels is rw4= (n×waa+m×wab)/(w1+w2), which is limited to a range of 0.1 to 3.75, more preferably 0.15 to 2. RV 5= (n x Waa x l1+m x Wab x L2-Nb x Waa x Wab) Da)/(D1 x ((l1+w1) (l2+w2) -L1 x L2)), the volume ratio is limited to the range of 0.03-3.4, more preferably to the range of 0.05-0.71.

Other parameters, such as the number of channels: preferably lower than 6, for example n, m may each independently be any one of 1,2,3,4, 5; more preferably, each of 2,3,4,5 is taken independently; most preferably, each is independently any one of 3,4, 5; the height of the polishing unit; the limitation range of parameters such as the depth of the channel is the same as that of the first embodiment, and the polishing pad shown in fig. 7 has excellent polishing performance and service life within the limitation range.

For the first to fourth embodiments, if the value of L1 or L2 is less than 10mm, the contact area of the polishing unit is reduced, the polishing rate is reduced, and if the value of L1 or L2 is greater than 20mm, the contact area of the polishing unit is excessively large, the distribution speed of the polishing liquid in the groove is affected, and scratches are caused. A W1 or W2 value of more than 5mm may cause too high a flow rate of the polishing liquid or decrease wettability of the polishing pad, and a W1 or W2 value of less than 0.5mm may cause residues abraded to be not effectively removed.

If Waa or Wab is less than 0.15mm, serious quality problems may occur in the processing of the polishing pad, even if the wafer is scratched, and if Waa or Wab is more than 0.6mm, the flow rate of the polishing liquid may be too fast to adversely affect the defectivity and the polishing rate.

If the range of RS1 is not in the range of [0.60-0.92], the defect level may be adversely affected.

If the range of RS2 is not within this [0.5-0.97], defectivity and polishing non-uniformity may be adversely affected.

If RS3 is less than 50%, the polishing rate may be seriously lost to be not good for production, and if RS3 is more than 85%, the polishing rate may satisfy basic requirements, but the scratch problem may be remarkably prominent.

RW4 in the range of [0.1-3.75] can well balance the flow speed of the large and small channels, thereby improving the distribution of the polishing solution and the waste residue removal efficiency.

N or m higher than 5 affects the processing quality of the grooves and the rigidity of the grooves and reduces the utilization ability of the polishing liquid, thereby reducing the grinding quality.

RV5 is within the range of [0.03-3.4], the overall transportation capacity of the polishing solution in the groove and the overall slag discharging capacity of the waste liquid can be reasonably balanced, and the polishing pad has excellent polishing performance.

Examples

(1) Preparation of polishing layer

The polyurethane polishing layer can be prepared by adopting a known prepolymer method, a one-step method and the like, and the method selected by the skilled person according to the needs does not influence the conception and the protection scope of the invention as long as the polishing pad related to the invention can be prepared. The polishing layer prepared by the invention uses 23.0 parts by mass of TDI (toluene diisocyanate), 46.3 parts by mass of PTMEG (polytetramethylene ether glycol) (molecular weight 701.0) and 30.7 parts by mass of MOCA (3, 3 '-dichloro-4, 4' -diaminodiphenylmethane); the microspheres are manufactured by Akzo Nobel, the brand of the microspheres is Expancel 551DE40D42, the mass of the microspheres accounts for 1.2% of the total mass of the polishing layer, the materials are added into a casting head, the materials are quickly mixed, the mixing speed is 5000rpm, the materials are cast into a mould to form a cylinder, the cylinder is sliced to obtain a sheet, and finally the sheet is grooved to obtain the polishing layer with a groove pattern, wherein the prepared polishing layer has the hardness of 56D and the density of 0.84g/cm ³; the polishing layer storage modulus E' was found to be 210MPa, tan delta 0.083, and KEL 364.9Pa ^-1 at 40℃and 1HZ using a dynamic mechanical analyzer.

(2) Preparation of polishing pad

The polishing pad of the invention can also be a polishing layer as described above; may further comprise a bottom layer; or a bottom layer and one or more intermediate layers disposed between the polishing layer and the bottom layer. The polishing layer, underlayer or intermediate layer, used to chemically mechanically polish the semiconductor substrate is not limiting to the invention.

The polishing layer of the polishing pad of the invention optionally also comprises an endpoint detection window, preferably the detection window is an integral window incorporated into the polishing layer.

The adhesive buffer layer used for the polishing pad is polyurethane impregnated non-woven fabric, the hardness is 74A, the compression rate is 7%, and the density is 0.3g/cm ³.

Code interpretation:

w1: length of interval between polishing units (parallelograms) in a direction of a axis, unit: mm;

w2: length of interval between polishing units (parallelograms) in the B-axis direction, unit: mm;

L1: length of the polishing unit (parallelogram) in the a-axis direction, unit: mm;

L2: length of the polishing unit (parallelogram) in the B-axis direction, unit: mm;

Waa, wab: average widths of the first channel and the second channel along the direction of the B axis and the direction of the A axis respectively are in mm;

n, m: the number of channels in the direction of the axis A and the direction of the axis B of the polishing unit, respectively;

Nb: the number of intersection points of the channels;

d1: average height of the polishing unit in mm;

Da: average depth of channels of the polishing unit in mm;

RS1：L1*L2/((L1+W1)*(L2+W2))

RS2：(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)/L1*L2

RS3：100％*(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)/((L1+W1)*(L2+W2))

RW4：(n*Waa+m*Wab)/(W1+W2)

RV5：((n*Waa*L1+m*Wab*L2-Nb*Waa*Wab)*Da)/(((L1+W1)*(L2+W2)-L1*L2)*D1)

Grinding parameters and evaluation method:

The polished wafer was Cu 10K wafer, the polishing solution was ANJI U3061:3061A diluted (10 times), 1% wt H ₂O₂ was additionally added, the flow rate was 230ml/min, the conditioner was a diamond disk of AK53 of Saesol, the pressure was 6lbf, the polishing head pressure was 2.7psi, the platen speed was 77rpm, the carrier speed was 71rpm, and the polishing time was 30s.

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

The polishing rate is calculated by measuring the removal rate of polishing at different locations of the wafer over a polishing time, and the measuring tool is Nano SpecII.

The polishing rate non-uniformity (Nu) was also calculated from Nano SpecII.

Defect level is a count of defects measured on a wafer using the instrument KLA-Tencor SP2 analyzer.

TABLE 1 groove sample set

Note that: the polishing layers used in examples 1-15 and comparative examples 1-10 were each 2mm thick.

The projected surfaces of the contact surfaces of the polishing units of examples 1 to 13 and example 15 were rectangular; the projection surface of the contact surface of the polishing elements of example 13 is rectangular, as shown in fig. 5, and the polishing elements in the same direction are staggered with the polishing elements in the other parallel direction; the contact surface of the polishing element of example 14 had a diamond shape projected with an included angle of 45 °; example 15 the channels of the polishing elements are non-uniformly spaced as shown in figure 4.

TABLE 2 geometric parameters of groove samples

Table 3 evaluation of polishing properties

Table 1 shows the dimensional parameters of the grooves of the examples and comparative examples of the present invention, table 2 shows the results of the grinding evaluation of the examples and comparative examples of the present invention, in which RS1, RS2, RS3, RW4, RV5 were calculated from the groove dimensions.

As can be seen from examples 1-13 and 15, the polishing pad has a rectangular projection surface, and has a preferable polishing rate (greater than) Lower defectivity (less than 100) and lower polishing rate non-uniformity (less than 6%). The polishing effect of example 14 was also good.

The RS3 of the comparative examples 1,2,6 and 10 is lower than 50%, the grinding rate is obviously reduced to about 5000 or below; RS1 of comparative example 3 was 0.93, more than the appropriate range of 0.6 to 0.92, and the defectivity increased to 154 (10 pieces) and 201 (100 pieces). RV5 of comparative example 4 was 3.9 and rw4 was 4.29, exceeding the ranges of 0.03-3.4 of RV5 and 0.1-3.75 of RW4, respectively, the defectivity increased to 232 (10 pieces) and 200 (100 pieces). RS3 of comparative example 7 was higher than 85%, resulting in excessively high defectivity, which increased to 503 (10 pieces) and 492 (100 pieces). Comparative example 9 has no small channels, defects close to 300 and above, and poor uniformity (9%).

The polishing pad which accords with the parameter range has optimal polishing performance by comprehensively considering various factors through a plurality of experimental researches and creative labor.

Claims

1. A polishing pad comprising a polishing layer, wherein the polishing layer comprises a polishing surface and at least one polishing unit positioned on the polishing surface, the polishing units have an average height D1, the polishing units form a polishing unit group, one end of the polishing unit group forms a contact surface, the contact surface is in direct contact with a material to be polished, and the projection of each polishing unit on the contact surface is in a parallelogram shape;

The plurality of polishing elements forming a first section, the polishing elements of the first section extending in a first direction and being uniformly spaced,

The polishing units of the second part extend in a direction parallel to the first direction and are uniformly spaced, the spacing of the polishing units of the first part is equal to the spacing of the polishing units of the second part, and the spacing distance in the first direction is W1;

S1＝L1*L2*sinθ

Sa＝n*Waa*L1*sinθ+m*Wab*L2*sinθ-Nb*Waa*Wab*sinθ

The effective contact area Ss of the polishing unit is as follows:

Ss＝S1-Sa＝sinθ*(L1*L2-n*Waa*L1-m*Wab*L2+Nb*Waa*Wab)

the polishing layer effective contact area ratio RS3 is defined as follows:

RS3＝Ss/((L1+W1)*(L2+W2)*sinθ)

= ((l1+w1) (l2+w2)) RS3 ranges from 50 to 85%;

The grinding area ratio is defined as follows:

rs1=l1×l2/((l1+w1) ×l2+w2), the range of RS1 is 0.60-0.92;

the effective contact area ratio RS2 of the polishing unit is defined as follows:

RS2 = Ss/S1, RS2 ranging from 0.5-0.97;

2. The polishing pad of claim 1, wherein L1 and L2 of the polishing elements range from 10-20mm.

3. The polishing pad of claim 1, wherein the effective contact area ratio RS3 is in the range of 60-70%.

4. The polishing pad of claim 1, wherein the plurality of first channels are uniformly spaced apart and/or the plurality of second channels are uniformly spaced apart.

5. The polishing pad of claim 1, wherein the polishing elements have the same or about the same height and the channels have the same or about the same depth.

6. The polishing pad of claim 1, wherein the average height D1 is 0.2-0.8 times the polishing layer thickness.

7. The polishing pad of claim 1, wherein the average depth Da of the channels is 0.4-1 times the polishing element height D1.

8. The polishing pad of claim 1, wherein Waa and Wab range from 0.15 mm to 0.6mm.

9. The polishing pad of claim 1, wherein W1 and W2 of the polishing element range from 0.5 mm to 5mm.

10. The polishing pad of claim 1, wherein the number of first channels is any one of 2-5 and/or the number of second channels is any one of 2-5.

11. The polishing pad of claim 1, wherein the polishing elements have a rectangular, square, or diamond shape projected on the contact surface.